diff --git a/layout/forms/nsColorControlFrame.cpp b/layout/forms/nsColorControlFrame.cpp
index bfde55cfca29..831fed903c0d 100644
--- a/layout/forms/nsColorControlFrame.cpp
+++ b/layout/forms/nsColorControlFrame.cpp
@@ -23,7 +23,7 @@ using mozilla::dom::HTMLInputElement;
 using mozilla::dom::CallerType;
 
 nsColorControlFrame::nsColorControlFrame(nsStyleContext* aContext)
-  : nsHTMLButtonControlFrame(aContext, LayoutFrameType::ColorControl)
+  : nsHTMLButtonControlFrame(aContext, kClassID, LayoutFrameType::ColorControl)
 {
 }
 
diff --git a/layout/forms/nsComboboxControlFrame.cpp b/layout/forms/nsComboboxControlFrame.cpp
index 89ad3a06a03c..981e22139f1d 100644
--- a/layout/forms/nsComboboxControlFrame.cpp
+++ b/layout/forms/nsComboboxControlFrame.cpp
@@ -223,7 +223,7 @@ static int32_t gReflowInx = -1;
 //------------------------------------------------------
 
 nsComboboxControlFrame::nsComboboxControlFrame(nsStyleContext* aContext)
-  : nsBlockFrame(aContext, LayoutFrameType::ComboboxControl)
+  : nsBlockFrame(aContext, kClassID, LayoutFrameType::ComboboxControl)
   , mDisplayFrame(nullptr)
   , mButtonFrame(nullptr)
   , mDropdownFrame(nullptr)
@@ -1286,7 +1286,7 @@ public:
 
   nsComboboxDisplayFrame(nsStyleContext* aContext,
                          nsComboboxControlFrame* aComboBox)
-    : nsBlockFrame(aContext, LayoutFrameType::ComboboxDisplay)
+    : nsBlockFrame(aContext, kClassID, LayoutFrameType::ComboboxDisplay)
     , mComboBox(aComboBox)
   {}
 
diff --git a/layout/forms/nsDateTimeControlFrame.cpp b/layout/forms/nsDateTimeControlFrame.cpp
index 6fffa50fe052..16ad0d1eb50e 100644
--- a/layout/forms/nsDateTimeControlFrame.cpp
+++ b/layout/forms/nsDateTimeControlFrame.cpp
@@ -43,7 +43,7 @@ NS_QUERYFRAME_HEAD(nsDateTimeControlFrame)
 NS_QUERYFRAME_TAIL_INHERITING(nsContainerFrame)
 
 nsDateTimeControlFrame::nsDateTimeControlFrame(nsStyleContext* aContext)
-  : nsContainerFrame(aContext, LayoutFrameType::DateTimeControl)
+  : nsContainerFrame(aContext, kClassID, LayoutFrameType::DateTimeControl)
 {
 }
 
diff --git a/layout/forms/nsFieldSetFrame.cpp b/layout/forms/nsFieldSetFrame.cpp
index bef2f08ec7de..f930c2f0abf2 100644
--- a/layout/forms/nsFieldSetFrame.cpp
+++ b/layout/forms/nsFieldSetFrame.cpp
@@ -32,7 +32,7 @@ NS_NewFieldSetFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
 NS_IMPL_FRAMEARENA_HELPERS(nsFieldSetFrame)
 
 nsFieldSetFrame::nsFieldSetFrame(nsStyleContext* aContext)
-  : nsContainerFrame(aContext, LayoutFrameType::FieldSet)
+  : nsContainerFrame(aContext, kClassID, LayoutFrameType::FieldSet)
   , mLegendRect(GetWritingMode())
 {
   mLegendSpace  = 0;
diff --git a/layout/forms/nsFileControlFrame.cpp b/layout/forms/nsFileControlFrame.cpp
index b2529e2658d0..a654b438e154 100644
--- a/layout/forms/nsFileControlFrame.cpp
+++ b/layout/forms/nsFileControlFrame.cpp
@@ -39,7 +39,7 @@ NS_NewFileControlFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
 NS_IMPL_FRAMEARENA_HELPERS(nsFileControlFrame)
 
 nsFileControlFrame::nsFileControlFrame(nsStyleContext* aContext)
-  : nsBlockFrame(aContext)
+  : nsBlockFrame(aContext, kClassID)
 {
   AddStateBits(NS_BLOCK_FLOAT_MGR);
 }
diff --git a/layout/forms/nsFormControlFrame.cpp b/layout/forms/nsFormControlFrame.cpp
index 46be54becd76..c3ec2f8b24cc 100644
--- a/layout/forms/nsFormControlFrame.cpp
+++ b/layout/forms/nsFormControlFrame.cpp
@@ -17,8 +17,9 @@ using namespace mozilla;
 
 //#define FCF_NOISY
 
-nsFormControlFrame::nsFormControlFrame(nsStyleContext* aContext)
-  : nsAtomicContainerFrame(aContext, LayoutFrameType::FormControl)
+nsFormControlFrame::nsFormControlFrame(nsStyleContext* aContext,
+                                       nsIFrame::ClassID aID)
+  : nsAtomicContainerFrame(aContext, aID, LayoutFrameType::FormControl)
 {
 }
 
diff --git a/layout/forms/nsFormControlFrame.h b/layout/forms/nsFormControlFrame.h
index 890631426aaf..a5376c452277 100644
--- a/layout/forms/nsFormControlFrame.h
+++ b/layout/forms/nsFormControlFrame.h
@@ -25,7 +25,7 @@ public:
     * @param aContent the content representing this frame
     * @param aParentFrame the parent frame
     */
-  explicit nsFormControlFrame(nsStyleContext*);
+  explicit nsFormControlFrame(nsStyleContext*, nsIFrame::ClassID);
 
   virtual bool IsFrameOfType(uint32_t aFlags) const override
   {
diff --git a/layout/forms/nsGfxButtonControlFrame.cpp b/layout/forms/nsGfxButtonControlFrame.cpp
index b225d920d297..df5a882755dc 100644
--- a/layout/forms/nsGfxButtonControlFrame.cpp
+++ b/layout/forms/nsGfxButtonControlFrame.cpp
@@ -19,7 +19,7 @@
 using namespace mozilla;
 
 nsGfxButtonControlFrame::nsGfxButtonControlFrame(nsStyleContext* aContext)
-  : nsHTMLButtonControlFrame(aContext, LayoutFrameType::GfxButtonControl)
+  : nsHTMLButtonControlFrame(aContext, kClassID, LayoutFrameType::GfxButtonControl)
 {
 }
 
diff --git a/layout/forms/nsGfxCheckboxControlFrame.cpp b/layout/forms/nsGfxCheckboxControlFrame.cpp
index eb4b0fd15190..101e3a4adf30 100644
--- a/layout/forms/nsGfxCheckboxControlFrame.cpp
+++ b/layout/forms/nsGfxCheckboxControlFrame.cpp
@@ -92,7 +92,7 @@ NS_IMPL_FRAMEARENA_HELPERS(nsGfxCheckboxControlFrame)
 //------------------------------------------------------------
 // Initialize GFX-rendered state
 nsGfxCheckboxControlFrame::nsGfxCheckboxControlFrame(nsStyleContext* aContext)
-: nsFormControlFrame(aContext)
+: nsFormControlFrame(aContext, kClassID)
 {
 }
 
diff --git a/layout/forms/nsGfxRadioControlFrame.cpp b/layout/forms/nsGfxRadioControlFrame.cpp
index 54654f0fcca8..a01bf492ab8a 100644
--- a/layout/forms/nsGfxRadioControlFrame.cpp
+++ b/layout/forms/nsGfxRadioControlFrame.cpp
@@ -25,7 +25,7 @@ NS_NewGfxRadioControlFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
 NS_IMPL_FRAMEARENA_HELPERS(nsGfxRadioControlFrame)
 
 nsGfxRadioControlFrame::nsGfxRadioControlFrame(nsStyleContext* aContext):
-  nsFormControlFrame(aContext)
+  nsFormControlFrame(aContext, kClassID)
 {
 }
 
diff --git a/layout/forms/nsHTMLButtonControlFrame.cpp b/layout/forms/nsHTMLButtonControlFrame.cpp
index 15ce2ba5e09f..2d6c2d86001b 100644
--- a/layout/forms/nsHTMLButtonControlFrame.cpp
+++ b/layout/forms/nsHTMLButtonControlFrame.cpp
@@ -27,8 +27,9 @@ NS_NewHTMLButtonControlFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
 NS_IMPL_FRAMEARENA_HELPERS(nsHTMLButtonControlFrame)
 
 nsHTMLButtonControlFrame::nsHTMLButtonControlFrame(nsStyleContext* aContext,
+                                                   nsIFrame::ClassID aID,
                                                    LayoutFrameType aType)
-  : nsContainerFrame(aContext, aType)
+  : nsContainerFrame(aContext, aID, aType)
 {
 }
 
diff --git a/layout/forms/nsHTMLButtonControlFrame.h b/layout/forms/nsHTMLButtonControlFrame.h
index 09b262a28183..d5dd58ec5aa6 100644
--- a/layout/forms/nsHTMLButtonControlFrame.h
+++ b/layout/forms/nsHTMLButtonControlFrame.h
@@ -19,7 +19,7 @@ class nsHTMLButtonControlFrame : public nsContainerFrame,
 {
 public:
   explicit nsHTMLButtonControlFrame(nsStyleContext* aContext)
-    : nsHTMLButtonControlFrame(aContext,
+    : nsHTMLButtonControlFrame(aContext, kClassID,
                                mozilla::LayoutFrameType::HTMLButtonControl)
   {}
 
@@ -106,7 +106,7 @@ public:
                                      nsStyleChangeList& aChangeList,
                                      nsChangeHint aHintForThisFrame) override;
 protected:
-  nsHTMLButtonControlFrame(nsStyleContext* aContext,
+  nsHTMLButtonControlFrame(nsStyleContext* aContext, nsIFrame::ClassID aID,
                            mozilla::LayoutFrameType aType);
 
   virtual bool IsInput() { return false; }
diff --git a/layout/forms/nsImageControlFrame.cpp b/layout/forms/nsImageControlFrame.cpp
index b6f10820aedb..37806f242a71 100644
--- a/layout/forms/nsImageControlFrame.cpp
+++ b/layout/forms/nsImageControlFrame.cpp
@@ -58,7 +58,7 @@ public:
 };
 
 nsImageControlFrame::nsImageControlFrame(nsStyleContext* aContext)
-  : nsImageFrame(aContext, LayoutFrameType::ImageControl)
+  : nsImageFrame(aContext, kClassID, LayoutFrameType::ImageControl)
 {
 }
 
diff --git a/layout/forms/nsLegendFrame.h b/layout/forms/nsLegendFrame.h
index 6b0911a9eb69..50bc4769a852 100644
--- a/layout/forms/nsLegendFrame.h
+++ b/layout/forms/nsLegendFrame.h
@@ -16,7 +16,7 @@ public:
   NS_DECL_FRAMEARENA_HELPERS(nsLegendFrame)
 
   explicit nsLegendFrame(nsStyleContext* aContext)
-    : nsBlockFrame(aContext, mozilla::LayoutFrameType::Legend)
+    : nsBlockFrame(aContext, kClassID, mozilla::LayoutFrameType::Legend)
   {}
 
   virtual void Reflow(nsPresContext* aPresContext,
diff --git a/layout/forms/nsListControlFrame.cpp b/layout/forms/nsListControlFrame.cpp
index bfc0866c5f9a..55682749fe6a 100644
--- a/layout/forms/nsListControlFrame.cpp
+++ b/layout/forms/nsListControlFrame.cpp
@@ -92,7 +92,7 @@ NS_IMPL_FRAMEARENA_HELPERS(nsListControlFrame)
 
 //---------------------------------------------------------
 nsListControlFrame::nsListControlFrame(nsStyleContext* aContext)
-  : nsHTMLScrollFrame(aContext, LayoutFrameType::ListControl, false)
+  : nsHTMLScrollFrame(aContext, kClassID, LayoutFrameType::ListControl, false)
   , mView(nullptr)
   , mMightNeedSecondPass(false)
   , mHasPendingInterruptAtStartOfReflow(false)
diff --git a/layout/forms/nsMeterFrame.cpp b/layout/forms/nsMeterFrame.cpp
index 27387a274537..fc5f9c292c47 100644
--- a/layout/forms/nsMeterFrame.cpp
+++ b/layout/forms/nsMeterFrame.cpp
@@ -39,7 +39,7 @@ NS_NewMeterFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
 NS_IMPL_FRAMEARENA_HELPERS(nsMeterFrame)
 
 nsMeterFrame::nsMeterFrame(nsStyleContext* aContext)
-  : nsContainerFrame(aContext, LayoutFrameType::Meter)
+  : nsContainerFrame(aContext, kClassID, LayoutFrameType::Meter)
   , mBarDiv(nullptr)
 {
 }
diff --git a/layout/forms/nsNumberControlFrame.cpp b/layout/forms/nsNumberControlFrame.cpp
index e17642410dc5..84eaf13531a0 100644
--- a/layout/forms/nsNumberControlFrame.cpp
+++ b/layout/forms/nsNumberControlFrame.cpp
@@ -50,7 +50,7 @@ NS_QUERYFRAME_HEAD(nsNumberControlFrame)
 NS_QUERYFRAME_TAIL_INHERITING(nsContainerFrame)
 
 nsNumberControlFrame::nsNumberControlFrame(nsStyleContext* aContext)
-  : nsContainerFrame(aContext, LayoutFrameType::NumberControl)
+  : nsContainerFrame(aContext, kClassID, LayoutFrameType::NumberControl)
   , mHandlingInputEvent(false)
 {
 }
diff --git a/layout/forms/nsProgressFrame.cpp b/layout/forms/nsProgressFrame.cpp
index e07e988639de..04fe62c91e1d 100644
--- a/layout/forms/nsProgressFrame.cpp
+++ b/layout/forms/nsProgressFrame.cpp
@@ -38,7 +38,7 @@ NS_NewProgressFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
 NS_IMPL_FRAMEARENA_HELPERS(nsProgressFrame)
 
 nsProgressFrame::nsProgressFrame(nsStyleContext* aContext)
-  : nsContainerFrame(aContext, LayoutFrameType::Progress)
+  : nsContainerFrame(aContext, kClassID, LayoutFrameType::Progress)
   , mBarDiv(nullptr)
 {
 }
diff --git a/layout/forms/nsRangeFrame.cpp b/layout/forms/nsRangeFrame.cpp
index 25991be34d75..224d4017afa0 100644
--- a/layout/forms/nsRangeFrame.cpp
+++ b/layout/forms/nsRangeFrame.cpp
@@ -47,7 +47,7 @@ NS_NewRangeFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
 }
 
 nsRangeFrame::nsRangeFrame(nsStyleContext* aContext)
-  : nsContainerFrame(aContext, LayoutFrameType::Range)
+  : nsContainerFrame(aContext, kClassID, LayoutFrameType::Range)
 {
 }
 
diff --git a/layout/forms/nsSelectsAreaFrame.h b/layout/forms/nsSelectsAreaFrame.h
index a0ab33e36c04..f190608c76f1 100644
--- a/layout/forms/nsSelectsAreaFrame.h
+++ b/layout/forms/nsSelectsAreaFrame.h
@@ -34,7 +34,7 @@ public:
   
 protected:
   explicit nsSelectsAreaFrame(nsStyleContext* aContext) :
-    nsBlockFrame(aContext),
+    nsBlockFrame(aContext, kClassID),
     mBSizeOfARow(0)
   {}
 
diff --git a/layout/forms/nsTextControlFrame.cpp b/layout/forms/nsTextControlFrame.cpp
index c2da2a07cff4..6e046fac1db9 100644
--- a/layout/forms/nsTextControlFrame.cpp
+++ b/layout/forms/nsTextControlFrame.cpp
@@ -103,7 +103,7 @@ private:
 #endif
 
 nsTextControlFrame::nsTextControlFrame(nsStyleContext* aContext)
-  : nsContainerFrame(aContext, LayoutFrameType::TextInput)
+  : nsContainerFrame(aContext, kClassID, LayoutFrameType::TextInput)
   , mFirstBaseline(NS_INTRINSIC_WIDTH_UNKNOWN)
   , mEditorHasBeenInitialized(false)
   , mIsProcessing(false)
diff --git a/layout/generic/BRFrame.cpp b/layout/generic/BRFrame.cpp
index 1644736bd606..89b50e127bbf 100644
--- a/layout/generic/BRFrame.cpp
+++ b/layout/generic/BRFrame.cpp
@@ -64,7 +64,7 @@ public:
 
 protected:
   explicit BRFrame(nsStyleContext* aContext)
-    : nsFrame(aContext, LayoutFrameType::Br)
+    : nsFrame(aContext, kClassID, LayoutFrameType::Br)
     , mAscent(NS_INTRINSIC_WIDTH_UNKNOWN)
   {}
 
diff --git a/layout/generic/DetailsFrame.cpp b/layout/generic/DetailsFrame.cpp
index faf541ef5b17..31b62362b919 100644
--- a/layout/generic/DetailsFrame.cpp
+++ b/layout/generic/DetailsFrame.cpp
@@ -31,7 +31,7 @@ NS_NewDetailsFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
 namespace mozilla {
 
 DetailsFrame::DetailsFrame(nsStyleContext* aContext)
-  : nsBlockFrame(aContext, LayoutFrameType::Details)
+  : nsBlockFrame(aContext, kClassID, LayoutFrameType::Details)
 {
 }
 
diff --git a/layout/generic/ViewportFrame.h b/layout/generic/ViewportFrame.h
index d63edc5e009a..ed0cef19c289 100644
--- a/layout/generic/ViewportFrame.h
+++ b/layout/generic/ViewportFrame.h
@@ -29,7 +29,7 @@ public:
   NS_DECL_FRAMEARENA_HELPERS(ViewportFrame)
 
   explicit ViewportFrame(nsStyleContext* aContext)
-    : ViewportFrame(aContext, mozilla::LayoutFrameType::Viewport)
+    : ViewportFrame(aContext, kClassID, mozilla::LayoutFrameType::Viewport)
   {}
 
   virtual ~ViewportFrame() { } // useful for debugging
@@ -77,8 +77,8 @@ public:
 #endif
 
 protected:
-  ViewportFrame(nsStyleContext* aContext, mozilla::LayoutFrameType aType)
-    : nsContainerFrame(aContext, aType)
+  ViewportFrame(nsStyleContext* aContext, ClassID aID, mozilla::LayoutFrameType aType)
+    : nsContainerFrame(aContext, aID, aType)
     , mView(nullptr)
   {}
 
diff --git a/layout/generic/nsAtomicContainerFrame.h b/layout/generic/nsAtomicContainerFrame.h
index 9e13094d4035..c3a09f1ec93a 100644
--- a/layout/generic/nsAtomicContainerFrame.h
+++ b/layout/generic/nsAtomicContainerFrame.h
@@ -40,9 +40,9 @@ public:
   }
 
 protected:
-  nsAtomicContainerFrame(nsStyleContext* aContext,
+  nsAtomicContainerFrame(nsStyleContext* aContext, ClassID aID,
                          mozilla::LayoutFrameType aType)
-    : nsContainerFrame(aContext, aType)
+    : nsContainerFrame(aContext, aID, aType)
   {}
 };
 
diff --git a/layout/generic/nsBackdropFrame.h b/layout/generic/nsBackdropFrame.h
index 1dad584de9c9..d678ad52f2d3 100644
--- a/layout/generic/nsBackdropFrame.h
+++ b/layout/generic/nsBackdropFrame.h
@@ -17,7 +17,7 @@ public:
   NS_DECL_FRAMEARENA_HELPERS(nsBackdropFrame)
 
   explicit nsBackdropFrame(nsStyleContext* aContext)
-    : nsFrame(aContext, mozilla::LayoutFrameType::Backdrop)
+    : nsFrame(aContext, kClassID, mozilla::LayoutFrameType::Backdrop)
   {}
 
 #ifdef DEBUG_FRAME_DUMP
diff --git a/layout/generic/nsBlockFrame.h b/layout/generic/nsBlockFrame.h
index 1f533ad06ffa..ab63d18d1358 100644
--- a/layout/generic/nsBlockFrame.h
+++ b/layout/generic/nsBlockFrame.h
@@ -396,8 +396,8 @@ public:
   };
 
 protected:
-  nsBlockFrame(nsStyleContext* aContext, mozilla::LayoutFrameType aType)
-    : nsContainerFrame(aContext, aType)
+  nsBlockFrame(nsStyleContext* aContext, ClassID aID, mozilla::LayoutFrameType aType)
+    : nsContainerFrame(aContext, aID, aType)
     , mMinWidth(NS_INTRINSIC_WIDTH_UNKNOWN)
     , mPrefWidth(NS_INTRINSIC_WIDTH_UNKNOWN)
   {
@@ -406,8 +406,8 @@ protected:
 #endif
   }
 
-  explicit nsBlockFrame(nsStyleContext* aContext)
-    : nsBlockFrame(aContext, mozilla::LayoutFrameType::Block)
+  explicit nsBlockFrame(nsStyleContext* aContext, ClassID aID = kClassID)
+    : nsBlockFrame(aContext, aID, mozilla::LayoutFrameType::Block)
   {}
 
   virtual ~nsBlockFrame();
diff --git a/layout/generic/nsBulletFrame.h b/layout/generic/nsBulletFrame.h
index 9bd4bdc18df3..ed7af572bbee 100644
--- a/layout/generic/nsBulletFrame.h
+++ b/layout/generic/nsBulletFrame.h
@@ -53,7 +53,7 @@ public:
 #endif
 
   explicit nsBulletFrame(nsStyleContext* aContext)
-    : nsFrame(aContext, mozilla::LayoutFrameType::Bullet)
+    : nsFrame(aContext, kClassID, mozilla::LayoutFrameType::Bullet)
     , mPadding(GetWritingMode())
     , mIntrinsicSize(GetWritingMode())
     , mOrdinal(0)
diff --git a/layout/generic/nsCanvasFrame.h b/layout/generic/nsCanvasFrame.h
index 530ca98c09f7..22740ca24098 100644
--- a/layout/generic/nsCanvasFrame.h
+++ b/layout/generic/nsCanvasFrame.h
@@ -34,7 +34,7 @@ class nsCanvasFrame final : public nsContainerFrame,
 {
 public:
   explicit nsCanvasFrame(nsStyleContext* aContext)
-    : nsContainerFrame(aContext, mozilla::LayoutFrameType::Canvas)
+    : nsContainerFrame(aContext, kClassID, mozilla::LayoutFrameType::Canvas)
     , mDoPaintFocus(false)
     , mAddedScrollPositionListener(false)
   {}
diff --git a/layout/generic/nsColumnSetFrame.cpp b/layout/generic/nsColumnSetFrame.cpp
index 480d975938e8..fda57d05b8f4 100644
--- a/layout/generic/nsColumnSetFrame.cpp
+++ b/layout/generic/nsColumnSetFrame.cpp
@@ -129,7 +129,7 @@ NS_NewColumnSetFrame(nsIPresShell* aPresShell, nsStyleContext* aContext, nsFrame
 NS_IMPL_FRAMEARENA_HELPERS(nsColumnSetFrame)
 
 nsColumnSetFrame::nsColumnSetFrame(nsStyleContext* aContext)
-  : nsContainerFrame(aContext, LayoutFrameType::ColumnSet)
+  : nsContainerFrame(aContext, kClassID, LayoutFrameType::ColumnSet)
   , mLastBalanceBSize(NS_INTRINSICSIZE)
 {
 }
diff --git a/layout/generic/nsContainerFrame.h b/layout/generic/nsContainerFrame.h
index 7241fc8b0c1c..542932174ea1 100644
--- a/layout/generic/nsContainerFrame.h
+++ b/layout/generic/nsContainerFrame.h
@@ -534,8 +534,8 @@ public:
 #endif
 
 protected:
-  nsContainerFrame(nsStyleContext* aContext, mozilla::LayoutFrameType aType)
-    : nsSplittableFrame(aContext, aType)
+  nsContainerFrame(nsStyleContext* aContext, ClassID aID, mozilla::LayoutFrameType aType)
+    : nsSplittableFrame(aContext, aID, aType)
   {}
 
   ~nsContainerFrame();
diff --git a/layout/generic/nsFirstLetterFrame.h b/layout/generic/nsFirstLetterFrame.h
index aae8553014f0..64a252e27d5a 100644
--- a/layout/generic/nsFirstLetterFrame.h
+++ b/layout/generic/nsFirstLetterFrame.h
@@ -17,7 +17,7 @@ public:
   NS_DECL_FRAMEARENA_HELPERS(nsFirstLetterFrame)
 
   explicit nsFirstLetterFrame(nsStyleContext* aContext)
-    : nsContainerFrame(aContext, mozilla::LayoutFrameType::Letter)
+    : nsContainerFrame(aContext, kClassID, mozilla::LayoutFrameType::Letter)
   {}
 
   virtual void BuildDisplayList(nsDisplayListBuilder*   aBuilder,
diff --git a/layout/generic/nsFlexContainerFrame.h b/layout/generic/nsFlexContainerFrame.h
index 1e9585d72cd7..6aa17af5577a 100644
--- a/layout/generic/nsFlexContainerFrame.h
+++ b/layout/generic/nsFlexContainerFrame.h
@@ -132,7 +132,7 @@ public:
 protected:
   // Protected constructor & destructor
   explicit nsFlexContainerFrame(nsStyleContext* aContext)
-    : nsContainerFrame(aContext, mozilla::LayoutFrameType::FlexContainer)
+    : nsContainerFrame(aContext, kClassID, mozilla::LayoutFrameType::FlexContainer)
     , mBaselineFromLastReflow(NS_INTRINSIC_WIDTH_UNKNOWN)
     , mLastBaselineFromLastReflow(NS_INTRINSIC_WIDTH_UNKNOWN)
   {}
diff --git a/layout/generic/nsFrame.cpp b/layout/generic/nsFrame.cpp
index b48149bc90cf..14be265b2e68 100644
--- a/layout/generic/nsFrame.cpp
+++ b/layout/generic/nsFrame.cpp
@@ -448,11 +448,11 @@ WeakFrame::Init(nsIFrame* aFrame)
 nsIFrame*
 NS_NewEmptyFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
 {
-  return new (aPresShell) nsFrame(aContext, LayoutFrameType::None);
+  return new (aPresShell) nsFrame(aContext);
 }
 
-nsFrame::nsFrame(nsStyleContext* aContext, LayoutFrameType aType)
-  : nsBox(aType)
+nsFrame::nsFrame(nsStyleContext* aContext, ClassID aID, LayoutFrameType aType)
+  : nsBox(aID, aType)
 {
   MOZ_COUNT_CTOR(nsFrame);
 
@@ -570,6 +570,7 @@ nsFrame::Init(nsIContent*       aContent,
               nsContainerFrame* aParent,
               nsIFrame*         aPrevInFlow)
 {
+  MOZ_ASSERT(nsQueryFrame::FrameIID(mClass) == GetFrameId());
   NS_PRECONDITION(!mContent, "Double-initing a frame?");
   NS_ASSERTION(IsFrameOfType(eDEBUGAllFrames) &&
                !IsFrameOfType(eDEBUGNoFrames),
diff --git a/layout/generic/nsFrame.h b/layout/generic/nsFrame.h
index 559532f039fe..9f354a027f4a 100644
--- a/layout/generic/nsFrame.h
+++ b/layout/generic/nsFrame.h
@@ -92,6 +92,7 @@
 
 #define NS_DECL_FRAMEARENA_HELPERS(class)                           \
   NS_DECL_QUERYFRAME_TARGET(class)                                  \
+  static constexpr nsIFrame::ClassID kClassID = nsIFrame::ClassID::class##_id;  \
   void* operator new(size_t, nsIPresShell*) MOZ_MUST_OVERRIDE;      \
   nsQueryFrame::FrameIID GetFrameId() override MOZ_MUST_OVERRIDE {  \
     return nsQueryFrame::class##_id;                                \
@@ -583,7 +584,9 @@ public:
 
 protected:
   // Protected constructor and destructor
-  explicit nsFrame(nsStyleContext* aContext, mozilla::LayoutFrameType aType);
+  nsFrame(nsStyleContext* aContext, ClassID aID, mozilla::LayoutFrameType aType);
+  explicit nsFrame(nsStyleContext* aContext)
+    : nsFrame(aContext, ClassID::nsFrame_id, mozilla::LayoutFrameType::None) {}
   virtual ~nsFrame();
 
   /**
diff --git a/layout/generic/nsFrameSetFrame.cpp b/layout/generic/nsFrameSetFrame.cpp
index 88b097bc3151..85c05e8a1bc6 100644
--- a/layout/generic/nsFrameSetFrame.cpp
+++ b/layout/generic/nsFrameSetFrame.cpp
@@ -158,7 +158,7 @@ public:
 
 protected:
   explicit nsHTMLFramesetBlankFrame(nsStyleContext* aContext)
-    : nsLeafFrame(aContext, LayoutFrameType::None)
+    : nsLeafFrame(aContext, kClassID, LayoutFrameType::None)
   {}
 
   virtual ~nsHTMLFramesetBlankFrame();
@@ -176,7 +176,7 @@ bool    nsHTMLFramesetFrame::gDragInProgress = false;
 #define DEFAULT_BORDER_WIDTH_PX 6
 
 nsHTMLFramesetFrame::nsHTMLFramesetFrame(nsStyleContext* aContext)
-  : nsContainerFrame(aContext, LayoutFrameType::FrameSet)
+  : nsContainerFrame(aContext, kClassID, LayoutFrameType::FrameSet)
 {
   mNumRows             = 0;
   mNumCols             = 0;
@@ -1336,7 +1336,7 @@ nsHTMLFramesetBorderFrame::nsHTMLFramesetBorderFrame(nsStyleContext* aContext,
                                                      int32_t aWidth,
                                                      bool aVertical,
                                                      bool aVisibility)
-  : nsLeafFrame(aContext, LayoutFrameType::None)
+  : nsLeafFrame(aContext, kClassID, LayoutFrameType::None)
   , mWidth(aWidth)
   , mVertical(aVertical)
   , mVisibility(aVisibility)
diff --git a/layout/generic/nsGfxScrollFrame.cpp b/layout/generic/nsGfxScrollFrame.cpp
index 90c6284f00fa..5de45ad50bbf 100644
--- a/layout/generic/nsGfxScrollFrame.cpp
+++ b/layout/generic/nsGfxScrollFrame.cpp
@@ -110,9 +110,10 @@ NS_NewHTMLScrollFrame(nsIPresShell* aPresShell, nsStyleContext* aContext, bool a
 NS_IMPL_FRAMEARENA_HELPERS(nsHTMLScrollFrame)
 
 nsHTMLScrollFrame::nsHTMLScrollFrame(nsStyleContext* aContext,
+                                     nsIFrame::ClassID aID,
                                      LayoutFrameType aType,
                                      bool aIsRoot)
-  : nsContainerFrame(aContext, aType)
+  : nsContainerFrame(aContext, aID, aType)
   , mHelper(ALLOW_THIS_IN_INITIALIZER_LIST(this), aIsRoot)
 {
 }
@@ -1161,7 +1162,7 @@ NS_IMPL_FRAMEARENA_HELPERS(nsXULScrollFrame)
 nsXULScrollFrame::nsXULScrollFrame(nsStyleContext* aContext,
                                    bool aIsRoot,
                                    bool aClipAllDescendants)
-  : nsBoxFrame(aContext, LayoutFrameType::Scroll, aIsRoot)
+  : nsBoxFrame(aContext, kClassID, LayoutFrameType::Scroll, aIsRoot)
   , mHelper(ALLOW_THIS_IN_INITIALIZER_LIST(this), aIsRoot)
 {
   SetXULLayoutManager(nullptr);
diff --git a/layout/generic/nsGfxScrollFrame.h b/layout/generic/nsGfxScrollFrame.h
index a5eeca49926c..cf7e5aaa64a2 100644
--- a/layout/generic/nsGfxScrollFrame.h
+++ b/layout/generic/nsGfxScrollFrame.h
@@ -1060,10 +1060,11 @@ public:
 
 protected:
   nsHTMLScrollFrame(nsStyleContext* aContext, bool aIsRoot)
-    : nsHTMLScrollFrame(aContext, mozilla::LayoutFrameType::Scroll, aIsRoot)
+    : nsHTMLScrollFrame(aContext, kClassID, mozilla::LayoutFrameType::Scroll, aIsRoot)
   {}
 
   nsHTMLScrollFrame(nsStyleContext* aContext,
+                    nsIFrame::ClassID aID,
                     mozilla::LayoutFrameType aType,
                     bool aIsRoot);
   void SetSuppressScrollbarUpdate(bool aSuppress) {
diff --git a/layout/generic/nsGridContainerFrame.h b/layout/generic/nsGridContainerFrame.h
index e85907cf9fda..ffdc4887bd0d 100644
--- a/layout/generic/nsGridContainerFrame.h
+++ b/layout/generic/nsGridContainerFrame.h
@@ -257,7 +257,7 @@ protected:
   friend nsContainerFrame* NS_NewGridContainerFrame(nsIPresShell* aPresShell,
                                                     nsStyleContext* aContext);
   explicit nsGridContainerFrame(nsStyleContext* aContext)
-    : nsContainerFrame(aContext, mozilla::LayoutFrameType::GridContainer)
+    : nsContainerFrame(aContext, kClassID, mozilla::LayoutFrameType::GridContainer)
     , mCachedMinISize(NS_INTRINSIC_WIDTH_UNKNOWN)
     , mCachedPrefISize(NS_INTRINSIC_WIDTH_UNKNOWN)
   {
diff --git a/layout/generic/nsHTMLCanvasFrame.h b/layout/generic/nsHTMLCanvasFrame.h
index 8bac0bb73cbe..9182a51b562c 100644
--- a/layout/generic/nsHTMLCanvasFrame.h
+++ b/layout/generic/nsHTMLCanvasFrame.h
@@ -36,7 +36,7 @@ public:
   NS_DECL_FRAMEARENA_HELPERS(nsHTMLCanvasFrame)
 
   explicit nsHTMLCanvasFrame(nsStyleContext* aContext)
-    : nsContainerFrame(aContext, mozilla::LayoutFrameType::HTMLCanvas)
+    : nsContainerFrame(aContext, kClassID, mozilla::LayoutFrameType::HTMLCanvas)
     , mBorderPadding(GetWritingMode())
   {}
 
diff --git a/layout/generic/nsIFrame.h b/layout/generic/nsIFrame.h
index f97963244444..5c346ada6b00 100644
--- a/layout/generic/nsIFrame.h
+++ b/layout/generic/nsIFrame.h
@@ -603,10 +603,11 @@ public:
   typedef mozilla::Sides Sides;
   typedef mozilla::LogicalSides LogicalSides;
   typedef mozilla::SmallPointerArray<mozilla::DisplayItemData> DisplayItemArray;
+  typedef nsQueryFrame::ClassID ClassID;
 
   NS_DECL_QUERYFRAME_TARGET(nsIFrame)
 
-  explicit nsIFrame(mozilla::LayoutFrameType aType)
+  explicit nsIFrame(ClassID aID, mozilla::LayoutFrameType aType)
     : mRect()
     , mContent(nullptr)
     , mStyleContext(nullptr)
@@ -615,6 +616,7 @@ public:
     , mPrevSibling(nullptr)
     , mState(NS_FRAME_FIRST_REFLOW | NS_FRAME_IS_DIRTY)
     , mType(aType)
+    , mClass(aID)
   {
     mozilla::PodZero(&mOverflow);
   }
@@ -3902,6 +3904,9 @@ protected:
   /** The type of the frame. */
   mozilla::LayoutFrameType mType;
 
+  /** The ClassID of the concrete class of this instance. */
+  ClassID mClass; // 1 byte
+
   // Helpers
   /**
    * Can we stop inside this frame when we're skipping non-rendered whitespace?
diff --git a/layout/generic/nsImageFrame.cpp b/layout/generic/nsImageFrame.cpp
index 4745598f2432..0ff7ed3f113d 100644
--- a/layout/generic/nsImageFrame.cpp
+++ b/layout/generic/nsImageFrame.cpp
@@ -135,8 +135,8 @@ NS_NewImageFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
 
 NS_IMPL_FRAMEARENA_HELPERS(nsImageFrame)
 
-nsImageFrame::nsImageFrame(nsStyleContext* aContext, LayoutFrameType aType)
-  : nsAtomicContainerFrame(aContext, aType)
+nsImageFrame::nsImageFrame(nsStyleContext* aContext, ClassID aID, LayoutFrameType aType)
+  : nsAtomicContainerFrame(aContext, aID, aType)
   , mComputedSize(0, 0)
   , mIntrinsicRatio(0, 0)
   , mDisplayingIcon(false)
diff --git a/layout/generic/nsImageFrame.h b/layout/generic/nsImageFrame.h
index 3a1e76ef51d6..d11555716a1b 100644
--- a/layout/generic/nsImageFrame.h
+++ b/layout/generic/nsImageFrame.h
@@ -72,8 +72,8 @@ public:
   NS_DECL_FRAMEARENA_HELPERS(nsImageFrame)
   NS_DECL_QUERYFRAME
 
-  explicit nsImageFrame(nsStyleContext* aContext)
-    : nsImageFrame(aContext, mozilla::LayoutFrameType::Image)
+  explicit nsImageFrame(nsStyleContext* aContext, ClassID aID = kClassID)
+    : nsImageFrame(aContext, aID, mozilla::LayoutFrameType::Image)
   {}
 
 
@@ -182,7 +182,7 @@ public:
   virtual void ReflowCallbackCanceled() override;
 
 protected:
-  nsImageFrame(nsStyleContext* aContext, mozilla::LayoutFrameType aType);
+  nsImageFrame(nsStyleContext* aContext, ClassID, mozilla::LayoutFrameType aType);
 
   virtual ~nsImageFrame();
 
diff --git a/layout/generic/nsInlineFrame.h b/layout/generic/nsInlineFrame.h
index 8693b7a0cafb..b2f424881ab6 100644
--- a/layout/generic/nsInlineFrame.h
+++ b/layout/generic/nsInlineFrame.h
@@ -140,13 +140,13 @@ protected:
     }
   };
 
-  nsInlineFrame(nsStyleContext* aContext, mozilla::LayoutFrameType aType)
-    : nsContainerFrame(aContext, aType)
+  nsInlineFrame(nsStyleContext* aContext, ClassID aID, mozilla::LayoutFrameType aType)
+    : nsContainerFrame(aContext, aID, aType)
     , mBaseline(NS_INTRINSIC_WIDTH_UNKNOWN)
   {}
 
-  explicit nsInlineFrame(nsStyleContext* aContext)
-    : nsInlineFrame(aContext, mozilla::LayoutFrameType::Inline)
+  explicit nsInlineFrame(nsStyleContext* aContext, ClassID aID = kClassID)
+    : nsInlineFrame(aContext, aID, mozilla::LayoutFrameType::Inline)
   {}
 
   virtual LogicalSides GetLogicalSkipSides(const ReflowInput* aReflowInput = nullptr) const override;
@@ -232,7 +232,7 @@ public:
 
 protected:
   explicit nsFirstLineFrame(nsStyleContext* aContext)
-    : nsInlineFrame(aContext, mozilla::LayoutFrameType::Line)
+    : nsInlineFrame(aContext, kClassID, mozilla::LayoutFrameType::Line)
   {}
 
   virtual nsIFrame* PullOneFrame(nsPresContext* aPresContext,
diff --git a/layout/generic/nsLeafFrame.h b/layout/generic/nsLeafFrame.h
index 93a27c42d992..b99ee1e6787c 100644
--- a/layout/generic/nsLeafFrame.h
+++ b/layout/generic/nsLeafFrame.h
@@ -77,8 +77,8 @@ public:
   }
 
 protected:
-  nsLeafFrame(nsStyleContext* aContext, mozilla::LayoutFrameType aType)
-    : nsFrame(aContext, aType)
+  nsLeafFrame(nsStyleContext* aContext, ClassID aID, mozilla::LayoutFrameType aType)
+    : nsFrame(aContext, aID, aType)
   {}
 
   virtual ~nsLeafFrame();
diff --git a/layout/generic/nsPageContentFrame.h b/layout/generic/nsPageContentFrame.h
index 8daa356236b0..b53edf829f26 100644
--- a/layout/generic/nsPageContentFrame.h
+++ b/layout/generic/nsPageContentFrame.h
@@ -44,7 +44,7 @@ public:
 
 protected:
   explicit nsPageContentFrame(nsStyleContext* aContext)
-    : ViewportFrame(aContext, mozilla::LayoutFrameType::PageContent)
+    : ViewportFrame(aContext, kClassID, mozilla::LayoutFrameType::PageContent)
   {}
 
   nsSharedPageData*         mPD;
diff --git a/layout/generic/nsPageFrame.cpp b/layout/generic/nsPageFrame.cpp
index 2752c848b852..65d2dd01a899 100644
--- a/layout/generic/nsPageFrame.cpp
+++ b/layout/generic/nsPageFrame.cpp
@@ -41,7 +41,7 @@ NS_QUERYFRAME_HEAD(nsPageFrame)
 NS_QUERYFRAME_TAIL_INHERITING(nsContainerFrame)
 
 nsPageFrame::nsPageFrame(nsStyleContext* aContext)
-  : nsContainerFrame(aContext, LayoutFrameType::Page)
+  : nsContainerFrame(aContext, kClassID, LayoutFrameType::Page)
 {
 }
 
@@ -682,7 +682,7 @@ NS_NewPageBreakFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
 NS_IMPL_FRAMEARENA_HELPERS(nsPageBreakFrame)
 
 nsPageBreakFrame::nsPageBreakFrame(nsStyleContext* aContext)
-  : nsLeafFrame(aContext, LayoutFrameType::PageBreak)
+  : nsLeafFrame(aContext, kClassID, LayoutFrameType::PageBreak)
   , mHaveReflowed(false)
 {
 }
diff --git a/layout/generic/nsPlaceholderFrame.h b/layout/generic/nsPlaceholderFrame.h
index 8c86e665ee7d..a8764ba6ea63 100644
--- a/layout/generic/nsPlaceholderFrame.h
+++ b/layout/generic/nsPlaceholderFrame.h
@@ -67,7 +67,7 @@ public:
                                           nsStyleContext* aContext,
                                           nsFrameState aTypeBit);
   nsPlaceholderFrame(nsStyleContext* aContext, nsFrameState aTypeBit)
-    : nsFrame(aContext, mozilla::LayoutFrameType::Placeholder)
+    : nsFrame(aContext, kClassID, mozilla::LayoutFrameType::Placeholder)
     , mOutOfFlowFrame(nullptr)
   {
     NS_PRECONDITION(aTypeBit == PLACEHOLDER_FOR_FLOAT ||
diff --git a/layout/generic/nsPluginFrame.cpp b/layout/generic/nsPluginFrame.cpp
index e194d94698a9..04b303083b8d 100644
--- a/layout/generic/nsPluginFrame.cpp
+++ b/layout/generic/nsPluginFrame.cpp
@@ -145,7 +145,7 @@ protected:
 };
 
 nsPluginFrame::nsPluginFrame(nsStyleContext* aContext)
-  : nsFrame(aContext, LayoutFrameType::Object)
+  : nsFrame(aContext, kClassID, LayoutFrameType::Object)
   , mInstanceOwner(nullptr)
   , mOuterView(nullptr)
   , mInnerView(nullptr)
diff --git a/layout/generic/nsQueryFrame.h b/layout/generic/nsQueryFrame.h
index 9a49a3e447e6..7122da4511e1 100644
--- a/layout/generic/nsQueryFrame.h
+++ b/layout/generic/nsQueryFrame.h
@@ -68,6 +68,15 @@ public:
     NON_FRAME_MARKER
   };
 
+  // A strict subset of FrameIID above for frame classes that we instantiate.
+  enum class ClassID : uint8_t {
+#define FRAME_ID(classname, ...) classname##_id,
+#define ABSTRACT_FRAME_ID(classname)
+#include "nsFrameIdList.h"
+#undef FRAME_ID
+#undef ABSTRACT_FRAME_ID
+  };
+
   virtual void* QueryFrame(FrameIID id) = 0;
 };
 
diff --git a/layout/generic/nsRubyBaseContainerFrame.h b/layout/generic/nsRubyBaseContainerFrame.h
index 48208be6f562..13b5330cdbd9 100644
--- a/layout/generic/nsRubyBaseContainerFrame.h
+++ b/layout/generic/nsRubyBaseContainerFrame.h
@@ -66,7 +66,7 @@ protected:
                                  nsStyleContext* aContext);
 
   explicit nsRubyBaseContainerFrame(nsStyleContext* aContext)
-    : nsContainerFrame(aContext, mozilla::LayoutFrameType::RubyBaseContainer)
+    : nsContainerFrame(aContext, kClassID, mozilla::LayoutFrameType::RubyBaseContainer)
   {}
 
   struct RubyReflowInput;
diff --git a/layout/generic/nsRubyBaseFrame.h b/layout/generic/nsRubyBaseFrame.h
index c6451302b313..404833cfaa03 100644
--- a/layout/generic/nsRubyBaseFrame.h
+++ b/layout/generic/nsRubyBaseFrame.h
@@ -32,7 +32,7 @@ protected:
   friend nsContainerFrame* NS_NewRubyBaseFrame(nsIPresShell* aPresShell,
                                                nsStyleContext* aContext);
   explicit nsRubyBaseFrame(nsStyleContext* aContext)
-    : nsRubyContentFrame(aContext, mozilla::LayoutFrameType::RubyBase)
+    : nsRubyContentFrame(aContext, kClassID, mozilla::LayoutFrameType::RubyBase)
   {}
 };
 
diff --git a/layout/generic/nsRubyContentFrame.h b/layout/generic/nsRubyContentFrame.h
index 3bd3f03cedb3..6c445b44dba8 100644
--- a/layout/generic/nsRubyContentFrame.h
+++ b/layout/generic/nsRubyContentFrame.h
@@ -28,8 +28,9 @@ public:
 
 protected:
   explicit nsRubyContentFrame(nsStyleContext* aContext,
+                              ClassID aID,
                               mozilla::LayoutFrameType aType)
-    : nsInlineFrame(aContext, aType)
+    : nsInlineFrame(aContext, aID, aType)
   {}
 };
 
diff --git a/layout/generic/nsRubyFrame.h b/layout/generic/nsRubyFrame.h
index be729e384588..60cc730b4b63 100644
--- a/layout/generic/nsRubyFrame.h
+++ b/layout/generic/nsRubyFrame.h
@@ -48,7 +48,7 @@ protected:
   friend nsContainerFrame* NS_NewRubyFrame(nsIPresShell* aPresShell,
                                            nsStyleContext* aContext);
   explicit nsRubyFrame(nsStyleContext* aContext)
-    : nsInlineFrame(aContext, mozilla::LayoutFrameType::Ruby)
+    : nsInlineFrame(aContext, kClassID, mozilla::LayoutFrameType::Ruby)
   {}
 
   void ReflowSegment(nsPresContext* aPresContext,
diff --git a/layout/generic/nsRubyTextContainerFrame.h b/layout/generic/nsRubyTextContainerFrame.h
index 69621e3dbedf..2a86d39a8606 100644
--- a/layout/generic/nsRubyTextContainerFrame.h
+++ b/layout/generic/nsRubyTextContainerFrame.h
@@ -56,7 +56,7 @@ protected:
                                  nsStyleContext* aContext);
 
   explicit nsRubyTextContainerFrame(nsStyleContext* aContext)
-    : nsContainerFrame(aContext, mozilla::LayoutFrameType::RubyTextContainer)
+    : nsContainerFrame(aContext, kClassID, mozilla::LayoutFrameType::RubyTextContainer)
     , mISize(0)
   {}
 
diff --git a/layout/generic/nsRubyTextFrame.h b/layout/generic/nsRubyTextFrame.h
index 2dee03baadc9..30c1f944283b 100644
--- a/layout/generic/nsRubyTextFrame.h
+++ b/layout/generic/nsRubyTextFrame.h
@@ -49,7 +49,7 @@ protected:
   friend nsContainerFrame* NS_NewRubyTextFrame(nsIPresShell* aPresShell,
                                                nsStyleContext* aContext);
   explicit nsRubyTextFrame(nsStyleContext* aContext)
-    : nsRubyContentFrame(aContext, mozilla::LayoutFrameType::RubyText)
+    : nsRubyContentFrame(aContext, kClassID, mozilla::LayoutFrameType::RubyText)
   {}
 };
 
diff --git a/layout/generic/nsSimplePageSequenceFrame.cpp b/layout/generic/nsSimplePageSequenceFrame.cpp
index ed3e3507540a..0da38322495b 100644
--- a/layout/generic/nsSimplePageSequenceFrame.cpp
+++ b/layout/generic/nsSimplePageSequenceFrame.cpp
@@ -45,7 +45,7 @@ NS_NewSimplePageSequenceFrame(nsIPresShell* aPresShell, nsStyleContext* aContext
 NS_IMPL_FRAMEARENA_HELPERS(nsSimplePageSequenceFrame)
 
 nsSimplePageSequenceFrame::nsSimplePageSequenceFrame(nsStyleContext* aContext)
-  : nsContainerFrame(aContext, LayoutFrameType::Sequence)
+  : nsContainerFrame(aContext, kClassID, LayoutFrameType::Sequence)
   , mTotalPages(-1)
   , mSelectionHeight(-1)
   , mYSelOffset(0)
diff --git a/layout/generic/nsSplittableFrame.h b/layout/generic/nsSplittableFrame.h
index c8b05fc16248..4718be862bc4 100644
--- a/layout/generic/nsSplittableFrame.h
+++ b/layout/generic/nsSplittableFrame.h
@@ -74,9 +74,9 @@ public:
   static void RemoveFromFlow(nsIFrame* aFrame);
 
 protected:
-  explicit nsSplittableFrame(nsStyleContext* aContext,
+  explicit nsSplittableFrame(nsStyleContext* aContext, ClassID aID,
                              mozilla::LayoutFrameType aType)
-    : nsFrame(aContext, aType)
+    : nsFrame(aContext, aID, aType)
     , mPrevContinuation(nullptr)
     , mNextContinuation(nullptr)
   {}
diff --git a/layout/generic/nsSubDocumentFrame.cpp b/layout/generic/nsSubDocumentFrame.cpp
index e573c28a6cd0..2727e52dcc8d 100644
--- a/layout/generic/nsSubDocumentFrame.cpp
+++ b/layout/generic/nsSubDocumentFrame.cpp
@@ -59,7 +59,7 @@ GetDocumentFromView(nsView* aView)
 }
 
 nsSubDocumentFrame::nsSubDocumentFrame(nsStyleContext* aContext)
-  : nsAtomicContainerFrame(aContext, LayoutFrameType::SubDocument)
+  : nsAtomicContainerFrame(aContext, kClassID, LayoutFrameType::SubDocument)
   , mOuterView(nullptr)
   , mInnerView(nullptr)
   , mIsInline(false)
diff --git a/layout/generic/nsTextFrame.cpp b/layout/generic/nsTextFrame.cpp
index f8c176edf960..0872403b1c63 100644
--- a/layout/generic/nsTextFrame.cpp
+++ b/layout/generic/nsTextFrame.cpp
@@ -4437,7 +4437,7 @@ public:
 
 protected:
   explicit nsContinuingTextFrame(nsStyleContext* aContext)
-    : nsTextFrame(aContext)
+    : nsTextFrame(aContext, kClassID)
   {}
 
   nsTextFrame* mPrevContinuation;
diff --git a/layout/generic/nsTextFrame.h b/layout/generic/nsTextFrame.h
index 825ce8fec27d..6ff5e1f9c0d6 100644
--- a/layout/generic/nsTextFrame.h
+++ b/layout/generic/nsTextFrame.h
@@ -50,8 +50,8 @@ class nsTextFrame : public nsFrame
   typedef gfxTextRun::Range Range;
 
 public:
-  explicit nsTextFrame(nsStyleContext* aContext)
-    : nsTextFrame(aContext, mozilla::LayoutFrameType::Text)
+  explicit nsTextFrame(nsStyleContext* aContext, ClassID aID = kClassID)
+    : nsTextFrame(aContext, aID, mozilla::LayoutFrameType::Text)
   {}
 
   NS_DECL_FRAMEARENA_HELPERS(nsTextFrame)
@@ -648,8 +648,8 @@ public:
   uint32_t CountGraphemeClusters() const;
 
 protected:
-  nsTextFrame(nsStyleContext* aContext, mozilla::LayoutFrameType aType)
-    : nsFrame(aContext, aType)
+  nsTextFrame(nsStyleContext* aContext, ClassID aID, mozilla::LayoutFrameType aType)
+    : nsFrame(aContext, aID, aType)
     , mNextContinuation(nullptr)
     , mContentOffset(0)
     , mContentLengthHint(0)
diff --git a/layout/generic/nsVideoFrame.cpp b/layout/generic/nsVideoFrame.cpp
index 84371f9b702d..8f625b58eb4b 100644
--- a/layout/generic/nsVideoFrame.cpp
+++ b/layout/generic/nsVideoFrame.cpp
@@ -75,7 +75,7 @@ SwapScaleWidthHeightForRotation(IntSize& aSize, VideoInfo::Rotation aDegrees)
 }
 
 nsVideoFrame::nsVideoFrame(nsStyleContext* aContext)
-  : nsContainerFrame(aContext, LayoutFrameType::HTMLVideo)
+  : nsContainerFrame(aContext, kClassID, LayoutFrameType::HTMLVideo)
 {
   EnableVisibilityTracking();
 }
diff --git a/layout/mathml/nsMathMLContainerFrame.h b/layout/mathml/nsMathMLContainerFrame.h
index 3c520812a92e..2068d8776961 100644
--- a/layout/mathml/nsMathMLContainerFrame.h
+++ b/layout/mathml/nsMathMLContainerFrame.h
@@ -32,8 +32,8 @@ class nsMathMLContainerFrame : public nsContainerFrame,
 {
   friend class nsMathMLmfencedFrame;
 public:
-  nsMathMLContainerFrame(nsStyleContext* aContext)
-    : nsContainerFrame(aContext, mozilla::LayoutFrameType::None)
+  nsMathMLContainerFrame(nsStyleContext* aContext, ClassID aID)
+    : nsContainerFrame(aContext, aID, mozilla::LayoutFrameType::None)
     , mIntrinsicWidth(NS_INTRINSIC_WIDTH_UNKNOWN)
     , mBlockStartAscent(0)
   {}
@@ -469,7 +469,9 @@ public:
   }
 
 protected:
-  explicit nsMathMLmathBlockFrame(nsStyleContext* aContext) : nsBlockFrame(aContext) {
+  explicit nsMathMLmathBlockFrame(nsStyleContext* aContext)
+    : nsBlockFrame(aContext, kClassID)
+  {
     // We should always have a float manager.  Not that things can really try
     // to float out of us anyway, but we need one for line layout.
     // Bug 1301881: Do we still need to set NS_BLOCK_FLOAT_MGR?
@@ -546,7 +548,7 @@ public:
 
 protected:
   explicit nsMathMLmathInlineFrame(nsStyleContext* aContext)
-    : nsInlineFrame(aContext)
+    : nsInlineFrame(aContext, kClassID)
   {}
 
   virtual ~nsMathMLmathInlineFrame() {}
diff --git a/layout/mathml/nsMathMLSelectedFrame.h b/layout/mathml/nsMathMLSelectedFrame.h
index e05b5e3d0be3..b1c6d67c16fd 100644
--- a/layout/mathml/nsMathMLSelectedFrame.h
+++ b/layout/mathml/nsMathMLSelectedFrame.h
@@ -48,8 +48,8 @@ public:
   virtual nsQueryFrame::FrameIID GetFrameId() override = 0;
 
 protected:
-  explicit nsMathMLSelectedFrame(nsStyleContext* aContext) :
-    nsMathMLContainerFrame(aContext),
+  nsMathMLSelectedFrame(nsStyleContext* aContext, ClassID aID) :
+    nsMathMLContainerFrame(aContext, aID),
     mSelectedFrame(nullptr),
     mInvalidMarkup(false) {}
   virtual ~nsMathMLSelectedFrame();
diff --git a/layout/mathml/nsMathMLTokenFrame.h b/layout/mathml/nsMathMLTokenFrame.h
index 436caaeb1af8..d80b11f93daa 100644
--- a/layout/mathml/nsMathMLTokenFrame.h
+++ b/layout/mathml/nsMathMLTokenFrame.h
@@ -59,7 +59,8 @@ public:
         ReflowOutput& aDesiredSize) override;
 
 protected:
-  explicit nsMathMLTokenFrame(nsStyleContext* aContext) : nsMathMLContainerFrame(aContext) {}
+  explicit nsMathMLTokenFrame(nsStyleContext* aContext, ClassID aID = kClassID)
+    : nsMathMLContainerFrame(aContext, aID) {}
   virtual ~nsMathMLTokenFrame();
 
   void MarkTextFramesAsTokenMathML();
diff --git a/layout/mathml/nsMathMLmactionFrame.h b/layout/mathml/nsMathMLmactionFrame.h
index b576b5548c4d..22440e9930c5 100644
--- a/layout/mathml/nsMathMLmactionFrame.h
+++ b/layout/mathml/nsMathMLmactionFrame.h
@@ -59,7 +59,7 @@ private:
 
 protected:
   explicit nsMathMLmactionFrame(nsStyleContext* aContext) :
-    nsMathMLSelectedFrame(aContext) {}
+    nsMathMLSelectedFrame(aContext, kClassID) {}
   virtual ~nsMathMLmactionFrame();
   
 private:
diff --git a/layout/mathml/nsMathMLmencloseFrame.cpp b/layout/mathml/nsMathMLmencloseFrame.cpp
index fd069259f89d..8a96b8cd2690 100644
--- a/layout/mathml/nsMathMLmencloseFrame.cpp
+++ b/layout/mathml/nsMathMLmencloseFrame.cpp
@@ -47,8 +47,8 @@ NS_NewMathMLmencloseFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
 
 NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmencloseFrame)
 
-nsMathMLmencloseFrame::nsMathMLmencloseFrame(nsStyleContext* aContext) :
-  nsMathMLContainerFrame(aContext), mNotationsToDraw(0),
+nsMathMLmencloseFrame::nsMathMLmencloseFrame(nsStyleContext* aContext, ClassID aID) :
+  nsMathMLContainerFrame(aContext, aID), mNotationsToDraw(0),
   mRuleThickness(0), mRadicalRuleThickness(0),
   mLongDivCharIndex(-1), mRadicalCharIndex(-1), mContentWidth(0)
 {
diff --git a/layout/mathml/nsMathMLmencloseFrame.h b/layout/mathml/nsMathMLmencloseFrame.h
index 8ae470ba4f93..4c5591660479 100644
--- a/layout/mathml/nsMathMLmencloseFrame.h
+++ b/layout/mathml/nsMathMLmencloseFrame.h
@@ -89,7 +89,7 @@ public:
   }
 
 protected:
-  explicit nsMathMLmencloseFrame(nsStyleContext* aContext);
+  explicit nsMathMLmencloseFrame(nsStyleContext* aContext, ClassID aID = kClassID);
   virtual ~nsMathMLmencloseFrame();
 
   nsresult PlaceInternal(DrawTarget*          aDrawTarget,
diff --git a/layout/mathml/nsMathMLmfencedFrame.h b/layout/mathml/nsMathMLmfencedFrame.h
index c37ede3dbd5f..3c6c07f0f72b 100644
--- a/layout/mathml/nsMathMLmfencedFrame.h
+++ b/layout/mathml/nsMathMLmfencedFrame.h
@@ -97,7 +97,7 @@ public:
 
 protected:
   explicit nsMathMLmfencedFrame(nsStyleContext* aContext)
-    : nsMathMLContainerFrame(aContext)
+    : nsMathMLContainerFrame(aContext, kClassID)
     , mOpenChar(nullptr)
     , mCloseChar(nullptr)
     , mSeparatorsChar(nullptr)
diff --git a/layout/mathml/nsMathMLmfracFrame.h b/layout/mathml/nsMathMLmfracFrame.h
index ef4a6fc09715..8e46bb2db360 100644
--- a/layout/mathml/nsMathMLmfracFrame.h
+++ b/layout/mathml/nsMathMLmfracFrame.h
@@ -96,7 +96,7 @@ public:
 
 protected:
   explicit nsMathMLmfracFrame(nsStyleContext* aContext)
-    : nsMathMLContainerFrame(aContext)
+    : nsMathMLContainerFrame(aContext, kClassID)
     , mLineRect()
     , mSlashChar(nullptr)
     , mLineThickness(0)
diff --git a/layout/mathml/nsMathMLmmultiscriptsFrame.h b/layout/mathml/nsMathMLmmultiscriptsFrame.h
index f0ab5659136c..bee5a1e32c6b 100644
--- a/layout/mathml/nsMathMLmmultiscriptsFrame.h
+++ b/layout/mathml/nsMathMLmmultiscriptsFrame.h
@@ -44,7 +44,8 @@ public:
   ScriptIncrement(nsIFrame* aFrame) override;
 
 protected:
-  explicit nsMathMLmmultiscriptsFrame(nsStyleContext* aContext) : nsMathMLContainerFrame(aContext) {}
+  explicit nsMathMLmmultiscriptsFrame(nsStyleContext* aContext)
+    : nsMathMLContainerFrame(aContext, kClassID) {}
   virtual ~nsMathMLmmultiscriptsFrame();
   
 
diff --git a/layout/mathml/nsMathMLmoFrame.h b/layout/mathml/nsMathMLmoFrame.h
index 2473e4baa553..481776d58ada 100644
--- a/layout/mathml/nsMathMLmoFrame.h
+++ b/layout/mathml/nsMathMLmoFrame.h
@@ -81,7 +81,7 @@ public:
 
 protected:
   explicit nsMathMLmoFrame(nsStyleContext* aContext) :
-    nsMathMLTokenFrame(aContext), mFlags(0), mMinSize(0), mMaxSize(0) {}
+    nsMathMLTokenFrame(aContext, kClassID), mFlags(0), mMinSize(0), mMaxSize(0) {}
   virtual ~nsMathMLmoFrame();
   
   nsMathMLChar     mMathMLChar; // Here is the MathMLChar that will deal with the operator.
diff --git a/layout/mathml/nsMathMLmpaddedFrame.h b/layout/mathml/nsMathMLmpaddedFrame.h
index 3102f9d87cfe..629bf3cd56b8 100644
--- a/layout/mathml/nsMathMLmpaddedFrame.h
+++ b/layout/mathml/nsMathMLmpaddedFrame.h
@@ -46,7 +46,7 @@ public:
 
 protected:
   explicit nsMathMLmpaddedFrame(nsStyleContext* aContext)
-    : nsMathMLContainerFrame(aContext)
+    : nsMathMLContainerFrame(aContext, kClassID)
     , mWidthSign(0)
     , mHeightSign(0)
     , mDepthSign(0)
diff --git a/layout/mathml/nsMathMLmrootFrame.cpp b/layout/mathml/nsMathMLmrootFrame.cpp
index fea24e00209f..f5516db1e5a2 100644
--- a/layout/mathml/nsMathMLmrootFrame.cpp
+++ b/layout/mathml/nsMathMLmrootFrame.cpp
@@ -29,7 +29,7 @@ NS_NewMathMLmrootFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
 NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmrootFrame)
 
 nsMathMLmrootFrame::nsMathMLmrootFrame(nsStyleContext* aContext) :
-  nsMathMLContainerFrame(aContext),
+  nsMathMLContainerFrame(aContext, kClassID),
   mSqrChar(),
   mBarRect()
 {
diff --git a/layout/mathml/nsMathMLmrowFrame.h b/layout/mathml/nsMathMLmrowFrame.h
index 118d3cd8579e..fbc747580153 100644
--- a/layout/mathml/nsMathMLmrowFrame.h
+++ b/layout/mathml/nsMathMLmrowFrame.h
@@ -47,7 +47,8 @@ public:
   }
 
 protected:
-  explicit nsMathMLmrowFrame(nsStyleContext* aContext) : nsMathMLContainerFrame(aContext) {}
+  explicit nsMathMLmrowFrame(nsStyleContext* aContext)
+    : nsMathMLContainerFrame(aContext, kClassID) {}
   virtual ~nsMathMLmrowFrame();
 };
 
diff --git a/layout/mathml/nsMathMLmspaceFrame.h b/layout/mathml/nsMathMLmspaceFrame.h
index 0bca9f5ebbf6..361632876d7a 100644
--- a/layout/mathml/nsMathMLmspaceFrame.h
+++ b/layout/mathml/nsMathMLmspaceFrame.h
@@ -37,7 +37,7 @@ public:
   
 protected:
   explicit nsMathMLmspaceFrame(nsStyleContext* aContext) :
-    nsMathMLContainerFrame(aContext), mWidth(0), mHeight(0), mDepth(0) {}
+    nsMathMLContainerFrame(aContext, kClassID), mWidth(0), mHeight(0), mDepth(0) {}
   virtual ~nsMathMLmspaceFrame();
 
   virtual nsresult
diff --git a/layout/mathml/nsMathMLmsqrtFrame.cpp b/layout/mathml/nsMathMLmsqrtFrame.cpp
index 096d5476935a..deb77ee408b8 100644
--- a/layout/mathml/nsMathMLmsqrtFrame.cpp
+++ b/layout/mathml/nsMathMLmsqrtFrame.cpp
@@ -19,7 +19,7 @@ NS_NewMathMLmsqrtFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
 NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmsqrtFrame)
 
 nsMathMLmsqrtFrame::nsMathMLmsqrtFrame(nsStyleContext* aContext) :
-  nsMathMLmencloseFrame(aContext)
+  nsMathMLmencloseFrame(aContext, kClassID)
 {
 }
 
diff --git a/layout/mathml/nsMathMLmtableFrame.cpp b/layout/mathml/nsMathMLmtableFrame.cpp
index 4e7df59a4075..e56dd2c43177 100644
--- a/layout/mathml/nsMathMLmtableFrame.cpp
+++ b/layout/mathml/nsMathMLmtableFrame.cpp
@@ -1305,7 +1305,7 @@ NS_NewMathMLmtdInnerFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
 NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmtdInnerFrame)
 
 nsMathMLmtdInnerFrame::nsMathMLmtdInnerFrame(nsStyleContext* aContext)
-  : nsBlockFrame(aContext)
+  : nsBlockFrame(aContext, kClassID)
 {
   // Make a copy of the parent nsStyleText for later modification.
   mUniqueStyleText = new (PresContext()) nsStyleText(*StyleText());
diff --git a/layout/mathml/nsMathMLmtableFrame.h b/layout/mathml/nsMathMLmtableFrame.h
index 262cf1c14956..2b0a3cae3274 100644
--- a/layout/mathml/nsMathMLmtableFrame.h
+++ b/layout/mathml/nsMathMLmtableFrame.h
@@ -49,7 +49,7 @@ public:
 
 protected:
   explicit nsMathMLmtableWrapperFrame(nsStyleContext* aContext)
-    : nsTableWrapperFrame(aContext)
+    : nsTableWrapperFrame(aContext, kClassID)
   {}
 
   virtual ~nsMathMLmtableWrapperFrame();
@@ -157,7 +157,7 @@ public:
 
 protected:
   explicit nsMathMLmtableFrame(nsStyleContext* aContext)
-    : nsTableFrame(aContext)
+    : nsTableFrame(aContext, kClassID)
     , mFrameSpacingX(0)
     , mFrameSpacingY(0)
     , mUseCSSSpacing(false)
@@ -232,7 +232,7 @@ public:
 
 protected:
   explicit nsMathMLmtrFrame(nsStyleContext* aContext)
-    : nsTableRowFrame(aContext)
+    : nsTableRowFrame(aContext, kClassID)
   {}
 
   virtual ~nsMathMLmtrFrame();
@@ -279,7 +279,7 @@ public:
 
 protected:
   nsMathMLmtdFrame(nsStyleContext* aContext, nsTableFrame* aTableFrame)
-    : nsTableCellFrame(aContext, aTableFrame)
+    : nsTableCellFrame(aContext, aTableFrame, kClassID)
   {
   }
 
diff --git a/layout/mathml/nsMathMLmunderoverFrame.h b/layout/mathml/nsMathMLmunderoverFrame.h
index e2875e2b77c3..375c26b4da9a 100644
--- a/layout/mathml/nsMathMLmunderoverFrame.h
+++ b/layout/mathml/nsMathMLmunderoverFrame.h
@@ -49,7 +49,7 @@ public:
 
 protected:
   explicit nsMathMLmunderoverFrame(nsStyleContext* aContext)
-    : nsMathMLContainerFrame(aContext)
+    : nsMathMLContainerFrame(aContext, kClassID)
     , mIncrementUnder(false)
     , mIncrementOver(false)
   {}
diff --git a/layout/mathml/nsMathMLsemanticsFrame.h b/layout/mathml/nsMathMLsemanticsFrame.h
index 1944c12a3d76..a7fb16e364d2 100644
--- a/layout/mathml/nsMathMLsemanticsFrame.h
+++ b/layout/mathml/nsMathMLsemanticsFrame.h
@@ -22,7 +22,7 @@ public:
 
 protected:
   explicit nsMathMLsemanticsFrame(nsStyleContext* aContext) :
-    nsMathMLSelectedFrame(aContext) {}
+    nsMathMLSelectedFrame(aContext, kClassID) {}
   virtual ~nsMathMLsemanticsFrame();
 
   nsIFrame* GetSelectedFrame() override;
diff --git a/layout/svg/SVGFEContainerFrame.cpp b/layout/svg/SVGFEContainerFrame.cpp
index 2a48abba39b1..1a1bff533ead 100644
--- a/layout/svg/SVGFEContainerFrame.cpp
+++ b/layout/svg/SVGFEContainerFrame.cpp
@@ -21,7 +21,7 @@ class SVGFEContainerFrame : public nsContainerFrame
   NS_NewSVGFEContainerFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 protected:
   explicit SVGFEContainerFrame(nsStyleContext* aContext)
-    : nsContainerFrame(aContext, mozilla::LayoutFrameType::SVGFEContainer)
+    : nsContainerFrame(aContext, kClassID, mozilla::LayoutFrameType::SVGFEContainer)
   {
     AddStateBits(NS_FRAME_SVG_LAYOUT | NS_FRAME_IS_NONDISPLAY);
   }
diff --git a/layout/svg/SVGFEImageFrame.cpp b/layout/svg/SVGFEImageFrame.cpp
index 457c86145212..f5109139199f 100644
--- a/layout/svg/SVGFEImageFrame.cpp
+++ b/layout/svg/SVGFEImageFrame.cpp
@@ -23,7 +23,7 @@ class SVGFEImageFrame final : public nsFrame
   NS_NewSVGFEImageFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 protected:
   explicit SVGFEImageFrame(nsStyleContext* aContext)
-    : nsFrame(aContext, LayoutFrameType::SVGFEImage)
+    : nsFrame(aContext, kClassID, LayoutFrameType::SVGFEImage)
   {
     AddStateBits(NS_FRAME_SVG_LAYOUT | NS_FRAME_IS_NONDISPLAY);
 
diff --git a/layout/svg/SVGFELeafFrame.cpp b/layout/svg/SVGFELeafFrame.cpp
index d16fc03f9372..06be20aa2c36 100644
--- a/layout/svg/SVGFELeafFrame.cpp
+++ b/layout/svg/SVGFELeafFrame.cpp
@@ -20,7 +20,7 @@ class SVGFELeafFrame final : public nsFrame
   NS_NewSVGFELeafFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 protected:
   explicit SVGFELeafFrame(nsStyleContext* aContext)
-    : nsFrame(aContext, LayoutFrameType::SVGFELeaf)
+    : nsFrame(aContext, kClassID, LayoutFrameType::SVGFELeaf)
   {
     AddStateBits(NS_FRAME_SVG_LAYOUT | NS_FRAME_IS_NONDISPLAY);
   }
diff --git a/layout/svg/SVGFEUnstyledLeafFrame.cpp b/layout/svg/SVGFEUnstyledLeafFrame.cpp
index 89d8cf567ac2..ac9ad75b6e6b 100644
--- a/layout/svg/SVGFEUnstyledLeafFrame.cpp
+++ b/layout/svg/SVGFEUnstyledLeafFrame.cpp
@@ -16,7 +16,7 @@ class SVGFEUnstyledLeafFrame : public nsFrame
   NS_NewSVGFEUnstyledLeafFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 protected:
   explicit SVGFEUnstyledLeafFrame(nsStyleContext* aContext)
-    : nsFrame(aContext, LayoutFrameType::SVGFEUnstyledLeaf)
+    : nsFrame(aContext, kClassID, LayoutFrameType::SVGFEUnstyledLeaf)
   {
     AddStateBits(NS_FRAME_SVG_LAYOUT | NS_FRAME_IS_NONDISPLAY);
   }
diff --git a/layout/svg/SVGGeometryFrame.h b/layout/svg/SVGGeometryFrame.h
index b3c1fce4fd07..9b9f381c2a93 100644
--- a/layout/svg/SVGGeometryFrame.h
+++ b/layout/svg/SVGGeometryFrame.h
@@ -49,14 +49,14 @@ class SVGGeometryFrame : public nsFrame
   friend class ::nsDisplaySVGGeometry;
 
 protected:
-  SVGGeometryFrame(nsStyleContext* aContext, mozilla::LayoutFrameType aType)
-    : nsFrame(aContext, aType)
+  SVGGeometryFrame(nsStyleContext* aContext, nsIFrame::ClassID aID, mozilla::LayoutFrameType aType)
+    : nsFrame(aContext, aID, aType)
   {
      AddStateBits(NS_FRAME_SVG_LAYOUT | NS_FRAME_MAY_BE_TRANSFORMED);
   }
 
   explicit SVGGeometryFrame(nsStyleContext* aContext)
-    : SVGGeometryFrame(aContext, mozilla::LayoutFrameType::SVGGeometry)
+    : SVGGeometryFrame(aContext, kClassID, mozilla::LayoutFrameType::SVGGeometry)
   {}
 
 public:
diff --git a/layout/svg/SVGTextFrame.h b/layout/svg/SVGTextFrame.h
index 0dc347bc92c2..861afbfc3283 100644
--- a/layout/svg/SVGTextFrame.h
+++ b/layout/svg/SVGTextFrame.h
@@ -193,7 +193,7 @@ class SVGTextFrame final : public nsSVGDisplayContainerFrame
 
 protected:
   explicit SVGTextFrame(nsStyleContext* aContext)
-    : nsSVGDisplayContainerFrame(aContext, mozilla::LayoutFrameType::SVGText)
+    : nsSVGDisplayContainerFrame(aContext, kClassID, mozilla::LayoutFrameType::SVGText)
     , mTrailingUndisplayedCharacters(0)
     , mFontSizeScaleFactor(1.0f)
     , mLastContextScale(1.0f)
diff --git a/layout/svg/SVGViewFrame.cpp b/layout/svg/SVGViewFrame.cpp
index 97e99d70427f..c10f0c0b8135 100644
--- a/layout/svg/SVGViewFrame.cpp
+++ b/layout/svg/SVGViewFrame.cpp
@@ -24,7 +24,7 @@ class SVGViewFrame : public nsFrame
   NS_NewSVGViewFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 protected:
   explicit SVGViewFrame(nsStyleContext* aContext)
-    : nsFrame(aContext, LayoutFrameType::SVGView)
+    : nsFrame(aContext, kClassID, LayoutFrameType::SVGView)
   {
     AddStateBits(NS_FRAME_IS_NONDISPLAY);
   }
diff --git a/layout/svg/nsSVGAFrame.cpp b/layout/svg/nsSVGAFrame.cpp
index 379f0449a57a..a928d23c170f 100644
--- a/layout/svg/nsSVGAFrame.cpp
+++ b/layout/svg/nsSVGAFrame.cpp
@@ -21,7 +21,7 @@ class nsSVGAFrame : public nsSVGDisplayContainerFrame
   NS_NewSVGAFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 protected:
   explicit nsSVGAFrame(nsStyleContext* aContext)
-    : nsSVGDisplayContainerFrame(aContext, LayoutFrameType::SVGA)
+    : nsSVGDisplayContainerFrame(aContext, kClassID, LayoutFrameType::SVGA)
   {}
 
 public:
diff --git a/layout/svg/nsSVGClipPathFrame.h b/layout/svg/nsSVGClipPathFrame.h
index f620a1fc25f9..05e6cb5eb92a 100644
--- a/layout/svg/nsSVGClipPathFrame.h
+++ b/layout/svg/nsSVGClipPathFrame.h
@@ -25,7 +25,7 @@ class nsSVGClipPathFrame final : public nsSVGContainerFrame
 
 protected:
   explicit nsSVGClipPathFrame(nsStyleContext* aContext)
-    : nsSVGContainerFrame(aContext, mozilla::LayoutFrameType::SVGClipPath)
+    : nsSVGContainerFrame(aContext, kClassID, mozilla::LayoutFrameType::SVGClipPath)
     , mIsBeingProcessed(false)
   {
     AddStateBits(NS_FRAME_IS_NONDISPLAY);
diff --git a/layout/svg/nsSVGContainerFrame.cpp b/layout/svg/nsSVGContainerFrame.cpp
index e1c04c9ccf6b..d4ab78d92b86 100644
--- a/layout/svg/nsSVGContainerFrame.cpp
+++ b/layout/svg/nsSVGContainerFrame.cpp
@@ -34,7 +34,7 @@ NS_NewSVGContainerFrame(nsIPresShell* aPresShell,
                         nsStyleContext* aContext)
 {
   nsIFrame* frame =
-    new (aPresShell) nsSVGContainerFrame(aContext, LayoutFrameType::None);
+    new (aPresShell) nsSVGContainerFrame(aContext, nsSVGContainerFrame::kClassID, LayoutFrameType::None);
   // If we were called directly, then the frame is for a <defs> or
   // an unknown element type. In both cases we prevent the content
   // from displaying directly.
@@ -43,7 +43,6 @@ NS_NewSVGContainerFrame(nsIPresShell* aPresShell,
 }
 
 NS_IMPL_FRAMEARENA_HELPERS(nsSVGContainerFrame)
-NS_IMPL_FRAMEARENA_HELPERS(nsSVGDisplayContainerFrame)
 
 void
 nsSVGContainerFrame::AppendFrames(ChildListID  aListID,
diff --git a/layout/svg/nsSVGContainerFrame.h b/layout/svg/nsSVGContainerFrame.h
index 410d2fb60728..9a9566cce109 100644
--- a/layout/svg/nsSVGContainerFrame.h
+++ b/layout/svg/nsSVGContainerFrame.h
@@ -40,8 +40,8 @@ class nsSVGContainerFrame : public nsContainerFrame
   friend nsIFrame* NS_NewSVGContainerFrame(nsIPresShell* aPresShell,
                                            nsStyleContext* aContext);
 protected:
-  nsSVGContainerFrame(nsStyleContext* aContext, mozilla::LayoutFrameType aType)
-    : nsContainerFrame(aContext, aType)
+  nsSVGContainerFrame(nsStyleContext* aContext, ClassID aID, mozilla::LayoutFrameType aType)
+    : nsContainerFrame(aContext, aID, aType)
   {
     AddStateBits(NS_FRAME_SVG_LAYOUT);
   }
@@ -110,16 +110,17 @@ class nsSVGDisplayContainerFrame : public nsSVGContainerFrame,
                                    public nsSVGDisplayableFrame
 {
 protected:
-  nsSVGDisplayContainerFrame(nsStyleContext* aContext,
+  nsSVGDisplayContainerFrame(nsStyleContext* aContext, nsIFrame::ClassID aID,
                              mozilla::LayoutFrameType aType)
-    : nsSVGContainerFrame(aContext, aType)
+    : nsSVGContainerFrame(aContext, aID, aType)
   {
      AddStateBits(NS_FRAME_MAY_BE_TRANSFORMED);
   }
 
 public:
   NS_DECL_QUERYFRAME
-  NS_DECL_FRAMEARENA_HELPERS(nsSVGDisplayContainerFrame)
+  NS_DECL_QUERYFRAME_TARGET(nsSVGDisplayContainerFrame)
+  NS_DECL_ABSTRACT_FRAME(nsSVGDisplayContainerFrame)
 
   // nsIFrame:
   virtual void InsertFrames(ChildListID     aListID,
diff --git a/layout/svg/nsSVGFilterFrame.h b/layout/svg/nsSVGFilterFrame.h
index d1887a57b662..e344a940b4fe 100644
--- a/layout/svg/nsSVGFilterFrame.h
+++ b/layout/svg/nsSVGFilterFrame.h
@@ -33,7 +33,7 @@ class nsSVGFilterFrame : public nsSVGContainerFrame
   NS_NewSVGFilterFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 protected:
   explicit nsSVGFilterFrame(nsStyleContext* aContext)
-    : nsSVGContainerFrame(aContext, mozilla::LayoutFrameType::SVGFilter)
+    : nsSVGContainerFrame(aContext, kClassID, mozilla::LayoutFrameType::SVGFilter)
     , mLoopFlag(false)
     , mNoHRefURI(false)
   {
diff --git a/layout/svg/nsSVGForeignObjectFrame.cpp b/layout/svg/nsSVGForeignObjectFrame.cpp
index 4d5215bec6e6..267bbe0cbd45 100644
--- a/layout/svg/nsSVGForeignObjectFrame.cpp
+++ b/layout/svg/nsSVGForeignObjectFrame.cpp
@@ -40,7 +40,7 @@ NS_NewSVGForeignObjectFrame(nsIPresShell   *aPresShell,
 NS_IMPL_FRAMEARENA_HELPERS(nsSVGForeignObjectFrame)
 
 nsSVGForeignObjectFrame::nsSVGForeignObjectFrame(nsStyleContext* aContext)
-  : nsContainerFrame(aContext, LayoutFrameType::SVGForeignObject)
+  : nsContainerFrame(aContext, kClassID, LayoutFrameType::SVGForeignObject)
   , mInReflow(false)
 {
   AddStateBits(NS_FRAME_REFLOW_ROOT | NS_FRAME_MAY_BE_TRANSFORMED |
diff --git a/layout/svg/nsSVGGFrame.h b/layout/svg/nsSVGGFrame.h
index 2525f02ef0f2..67cb0addca3d 100644
--- a/layout/svg/nsSVGGFrame.h
+++ b/layout/svg/nsSVGGFrame.h
@@ -16,12 +16,12 @@ class nsSVGGFrame : public nsSVGDisplayContainerFrame
   friend nsIFrame*
   NS_NewSVGGFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 protected:
-  nsSVGGFrame(nsStyleContext* aContext, mozilla::LayoutFrameType aType)
-    : nsSVGDisplayContainerFrame(aContext, aType)
+  nsSVGGFrame(nsStyleContext* aContext, nsIFrame::ClassID aID, mozilla::LayoutFrameType aType)
+    : nsSVGDisplayContainerFrame(aContext, aID, aType)
   {}
 
-  explicit nsSVGGFrame(nsStyleContext* aContext)
-    : nsSVGGFrame(aContext, mozilla::LayoutFrameType::SVGG)
+  explicit nsSVGGFrame(nsStyleContext* aContext, nsIFrame::ClassID aID = kClassID)
+    : nsSVGGFrame(aContext, aID, mozilla::LayoutFrameType::SVGG)
   {}
 
 public:
diff --git a/layout/svg/nsSVGGenericContainerFrame.h b/layout/svg/nsSVGGenericContainerFrame.h
index 4664e4f8e7c7..f918dcc975f9 100644
--- a/layout/svg/nsSVGGenericContainerFrame.h
+++ b/layout/svg/nsSVGGenericContainerFrame.h
@@ -25,7 +25,7 @@ class nsSVGGenericContainerFrame final : public nsSVGDisplayContainerFrame
 
 protected:
   explicit nsSVGGenericContainerFrame(nsStyleContext* aContext)
-    : nsSVGDisplayContainerFrame(aContext,
+    : nsSVGDisplayContainerFrame(aContext, kClassID,
                                  mozilla::LayoutFrameType::SVGGenericContainer)
   {}
 
diff --git a/layout/svg/nsSVGGradientFrame.cpp b/layout/svg/nsSVGGradientFrame.cpp
index 1863e7ac312d..dcee35cf31ee 100644
--- a/layout/svg/nsSVGGradientFrame.cpp
+++ b/layout/svg/nsSVGGradientFrame.cpp
@@ -26,8 +26,9 @@ using namespace mozilla::gfx;
 // Implementation
 
 nsSVGGradientFrame::nsSVGGradientFrame(nsStyleContext* aContext,
+                                       ClassID aID,
                                        LayoutFrameType aType)
-  : nsSVGPaintServerFrame(aContext, aType)
+  : nsSVGPaintServerFrame(aContext, aID, aType)
   , mSource(nullptr)
   , mLoopFlag(false)
   , mNoHRefURI(false)
diff --git a/layout/svg/nsSVGGradientFrame.h b/layout/svg/nsSVGGradientFrame.h
index 8ab05a2c3b95..cbe9d1baeaf8 100644
--- a/layout/svg/nsSVGGradientFrame.h
+++ b/layout/svg/nsSVGGradientFrame.h
@@ -40,7 +40,7 @@ class nsSVGGradientFrame : public nsSVGPaintServerFrame
   typedef mozilla::gfx::ExtendMode ExtendMode;
 
 protected:
-  nsSVGGradientFrame(nsStyleContext* aContext, mozilla::LayoutFrameType aType);
+  nsSVGGradientFrame(nsStyleContext* aContext, ClassID aID, mozilla::LayoutFrameType aType);
 
 public:
   NS_DECL_ABSTRACT_FRAME(nsSVGGradientFrame)
@@ -127,7 +127,7 @@ class nsSVGLinearGradientFrame : public nsSVGGradientFrame
                                                 nsStyleContext* aContext);
 protected:
   explicit nsSVGLinearGradientFrame(nsStyleContext* aContext)
-    : nsSVGGradientFrame(aContext, mozilla::LayoutFrameType::SVGLinearGradient)
+    : nsSVGGradientFrame(aContext, kClassID, mozilla::LayoutFrameType::SVGLinearGradient)
   {}
 
 public:
@@ -169,7 +169,7 @@ class nsSVGRadialGradientFrame : public nsSVGGradientFrame
                                                 nsStyleContext* aContext);
 protected:
   explicit nsSVGRadialGradientFrame(nsStyleContext* aContext)
-    : nsSVGGradientFrame(aContext, mozilla::LayoutFrameType::SVGRadialGradient)
+    : nsSVGGradientFrame(aContext, kClassID, mozilla::LayoutFrameType::SVGRadialGradient)
   {}
 
 public:
diff --git a/layout/svg/nsSVGImageFrame.h b/layout/svg/nsSVGImageFrame.h
index da554d7703ac..fe7343d6f2c9 100644
--- a/layout/svg/nsSVGImageFrame.h
+++ b/layout/svg/nsSVGImageFrame.h
@@ -59,7 +59,7 @@ class nsSVGImageFrame final
 
 protected:
   explicit nsSVGImageFrame(nsStyleContext* aContext)
-    : SVGGeometryFrame(aContext, LayoutFrameType::SVGImage)
+    : SVGGeometryFrame(aContext, kClassID, LayoutFrameType::SVGImage)
     , mReflowCallbackPosted(false)
     , mForceSyncDecoding(false)
   {
diff --git a/layout/svg/nsSVGInnerSVGFrame.h b/layout/svg/nsSVGInnerSVGFrame.h
index cab4ecc7751d..5a60f1d578d7 100644
--- a/layout/svg/nsSVGInnerSVGFrame.h
+++ b/layout/svg/nsSVGInnerSVGFrame.h
@@ -21,7 +21,7 @@ class nsSVGInnerSVGFrame final
   NS_NewSVGInnerSVGFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 protected:
   explicit nsSVGInnerSVGFrame(nsStyleContext* aContext)
-    : nsSVGDisplayContainerFrame(aContext,
+    : nsSVGDisplayContainerFrame(aContext, kClassID,
                                  mozilla::LayoutFrameType::SVGInnerSVG)
   {
   }
diff --git a/layout/svg/nsSVGMarkerFrame.h b/layout/svg/nsSVGMarkerFrame.h
index ed9bf54261bd..728fd82f0da8 100644
--- a/layout/svg/nsSVGMarkerFrame.h
+++ b/layout/svg/nsSVGMarkerFrame.h
@@ -35,7 +35,7 @@ class nsSVGMarkerFrame final : public nsSVGContainerFrame
   NS_NewSVGMarkerFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 protected:
   explicit nsSVGMarkerFrame(nsStyleContext* aContext)
-    : nsSVGContainerFrame(aContext, mozilla::LayoutFrameType::SVGMarker)
+    : nsSVGContainerFrame(aContext, kClassID, mozilla::LayoutFrameType::SVGMarker)
     , mMarkedFrame(nullptr)
     , mInUse(false)
     , mInUse2(false)
@@ -141,7 +141,7 @@ class nsSVGMarkerAnonChildFrame final : public nsSVGDisplayContainerFrame
                                 nsStyleContext* aContext);
 
   explicit nsSVGMarkerAnonChildFrame(nsStyleContext* aContext)
-    : nsSVGDisplayContainerFrame(aContext,
+    : nsSVGDisplayContainerFrame(aContext, kClassID,
                                  mozilla::LayoutFrameType::SVGMarkerAnonChild)
   {}
 
diff --git a/layout/svg/nsSVGMaskFrame.h b/layout/svg/nsSVGMaskFrame.h
index 40ec0dabf417..371607807f80 100644
--- a/layout/svg/nsSVGMaskFrame.h
+++ b/layout/svg/nsSVGMaskFrame.h
@@ -42,7 +42,7 @@ class nsSVGMaskFrame final : public nsSVGContainerFrame
 
 protected:
   explicit nsSVGMaskFrame(nsStyleContext* aContext)
-    : nsSVGContainerFrame(aContext, mozilla::LayoutFrameType::SVGMask)
+    : nsSVGContainerFrame(aContext, kClassID, mozilla::LayoutFrameType::SVGMask)
     , mInUse(false)
   {
     AddStateBits(NS_FRAME_IS_NONDISPLAY);
diff --git a/layout/svg/nsSVGOuterSVGFrame.cpp b/layout/svg/nsSVGOuterSVGFrame.cpp
index 9ddff17b2ecb..52c4a26c8568 100644
--- a/layout/svg/nsSVGOuterSVGFrame.cpp
+++ b/layout/svg/nsSVGOuterSVGFrame.cpp
@@ -65,7 +65,7 @@ NS_NewSVGOuterSVGFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
 NS_IMPL_FRAMEARENA_HELPERS(nsSVGOuterSVGFrame)
 
 nsSVGOuterSVGFrame::nsSVGOuterSVGFrame(nsStyleContext* aContext)
-  : nsSVGDisplayContainerFrame(aContext, LayoutFrameType::SVGOuterSVG)
+  : nsSVGDisplayContainerFrame(aContext, kClassID, LayoutFrameType::SVGOuterSVG)
   , mCallingReflowSVG(false)
   , mFullZoom(aContext->PresContext()->GetFullZoom())
   , mViewportInitialized(false)
diff --git a/layout/svg/nsSVGOuterSVGFrame.h b/layout/svg/nsSVGOuterSVGFrame.h
index e79234e717aa..17fd30f1ea5c 100644
--- a/layout/svg/nsSVGOuterSVGFrame.h
+++ b/layout/svg/nsSVGOuterSVGFrame.h
@@ -233,7 +233,7 @@ class nsSVGOuterSVGAnonChildFrame final : public nsSVGDisplayContainerFrame
                                   nsStyleContext* aContext);
 
   explicit nsSVGOuterSVGAnonChildFrame(nsStyleContext* aContext)
-    : nsSVGDisplayContainerFrame(aContext,
+    : nsSVGDisplayContainerFrame(aContext, kClassID,
                                  mozilla::LayoutFrameType::SVGOuterSVGAnonChild)
   {}
 
diff --git a/layout/svg/nsSVGPaintServerFrame.h b/layout/svg/nsSVGPaintServerFrame.h
index 5d698e7b7106..e387f4d99bb2 100644
--- a/layout/svg/nsSVGPaintServerFrame.h
+++ b/layout/svg/nsSVGPaintServerFrame.h
@@ -57,9 +57,9 @@ class nsSVGPaintServerFrame : public nsSVGContainerFrame
 protected:
   typedef mozilla::gfx::DrawTarget DrawTarget;
 
-  explicit nsSVGPaintServerFrame(nsStyleContext* aContext,
+  explicit nsSVGPaintServerFrame(nsStyleContext* aContext, ClassID aID,
                                  mozilla::LayoutFrameType aType)
-    : nsSVGContainerFrame(aContext, aType)
+    : nsSVGContainerFrame(aContext, aID, aType)
   {
     AddStateBits(NS_FRAME_IS_NONDISPLAY);
   }
diff --git a/layout/svg/nsSVGPatternFrame.cpp b/layout/svg/nsSVGPatternFrame.cpp
index 23cf00d317e8..298876920a13 100644
--- a/layout/svg/nsSVGPatternFrame.cpp
+++ b/layout/svg/nsSVGPatternFrame.cpp
@@ -34,7 +34,7 @@ using namespace mozilla::image;
 // Implementation
 
 nsSVGPatternFrame::nsSVGPatternFrame(nsStyleContext* aContext)
-  : nsSVGPaintServerFrame(aContext, LayoutFrameType::SVGPattern)
+  : nsSVGPaintServerFrame(aContext, kClassID, LayoutFrameType::SVGPattern)
   , mSource(nullptr)
   , mLoopFlag(false)
   , mNoHRefURI(false)
diff --git a/layout/svg/nsSVGStopFrame.cpp b/layout/svg/nsSVGStopFrame.cpp
index a7ed123c4464..934e226fcadf 100644
--- a/layout/svg/nsSVGStopFrame.cpp
+++ b/layout/svg/nsSVGStopFrame.cpp
@@ -20,7 +20,7 @@ class nsSVGStopFrame : public nsFrame
   NS_NewSVGStopFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 protected:
   explicit nsSVGStopFrame(nsStyleContext* aContext)
-    : nsFrame(aContext, LayoutFrameType::SVGStop)
+    : nsFrame(aContext, kClassID, LayoutFrameType::SVGStop)
   {
     AddStateBits(NS_FRAME_IS_NONDISPLAY);
   }
diff --git a/layout/svg/nsSVGSwitchFrame.cpp b/layout/svg/nsSVGSwitchFrame.cpp
index 23f8611f7c4d..72b03b9f9f05 100644
--- a/layout/svg/nsSVGSwitchFrame.cpp
+++ b/layout/svg/nsSVGSwitchFrame.cpp
@@ -19,7 +19,7 @@ class nsSVGSwitchFrame final : public nsSVGGFrame
   NS_NewSVGSwitchFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 protected:
   explicit nsSVGSwitchFrame(nsStyleContext* aContext)
-    : nsSVGGFrame(aContext, LayoutFrameType::SVGSwitch)
+    : nsSVGGFrame(aContext, kClassID, LayoutFrameType::SVGSwitch)
   {}
 
 public:
diff --git a/layout/svg/nsSVGUseFrame.cpp b/layout/svg/nsSVGUseFrame.cpp
index 21f4f2a3d3e4..a2848a132cea 100644
--- a/layout/svg/nsSVGUseFrame.cpp
+++ b/layout/svg/nsSVGUseFrame.cpp
@@ -21,7 +21,7 @@ class nsSVGUseFrame final
 
 protected:
   explicit nsSVGUseFrame(nsStyleContext* aContext)
-    : nsSVGGFrame(aContext, LayoutFrameType::SVGUse)
+    : nsSVGGFrame(aContext, kClassID, LayoutFrameType::SVGUse)
     , mHasValidDimensions(true)
   {}
 
diff --git a/layout/tables/nsTableCellFrame.cpp b/layout/tables/nsTableCellFrame.cpp
index 1e94e6da430a..4f34bb3c8579 100644
--- a/layout/tables/nsTableCellFrame.cpp
+++ b/layout/tables/nsTableCellFrame.cpp
@@ -43,8 +43,9 @@ using namespace mozilla::image;
 
 nsTableCellFrame::nsTableCellFrame(nsStyleContext* aContext,
                                    nsTableFrame* aTableFrame,
+                                   ClassID aID,
                                    LayoutFrameType aType)
-  : nsContainerFrame(aContext, aType)
+  : nsContainerFrame(aContext, aID, aType)
   , mDesiredSize(aTableFrame->GetWritingMode())
 {
   mColIndex = 0;
@@ -1086,7 +1087,7 @@ nsTableCellFrame::GetFrameName(nsAString& aResult) const
 
 nsBCTableCellFrame::nsBCTableCellFrame(nsStyleContext* aContext,
                                        nsTableFrame* aTableFrame)
-  : nsTableCellFrame(aContext, aTableFrame, LayoutFrameType::BCTableCell)
+  : nsTableCellFrame(aContext, aTableFrame, kClassID, LayoutFrameType::BCTableCell)
 {
   mBStartBorder = mIEndBorder = mBEndBorder = mIStartBorder = 0;
 }
diff --git a/layout/tables/nsTableCellFrame.h b/layout/tables/nsTableCellFrame.h
index d93638fdcb15..c5f537cc128f 100644
--- a/layout/tables/nsTableCellFrame.h
+++ b/layout/tables/nsTableCellFrame.h
@@ -48,9 +48,9 @@ public:
 
   // default constructor supplied by the compiler
 
-  nsTableCellFrame(nsStyleContext* aContext, nsTableFrame* aTableFrame)
-    : nsTableCellFrame(aContext,
-                       aTableFrame,
+  nsTableCellFrame(nsStyleContext* aContext, nsTableFrame* aTableFrame,
+                   ClassID aID = kClassID)
+    : nsTableCellFrame(aContext, aTableFrame, aID,
                        mozilla::LayoutFrameType::TableCell)
   {}
 
@@ -234,6 +234,7 @@ public:
 protected:
   nsTableCellFrame(nsStyleContext* aContext,
                    nsTableFrame* aTableFrame,
+                   ClassID aID,
                    mozilla::LayoutFrameType aType);
 
   virtual LogicalSides
diff --git a/layout/tables/nsTableColFrame.cpp b/layout/tables/nsTableColFrame.cpp
index be401bedd09c..585e30108890 100644
--- a/layout/tables/nsTableColFrame.cpp
+++ b/layout/tables/nsTableColFrame.cpp
@@ -24,7 +24,7 @@ using namespace mozilla;
 using namespace mozilla;
 
 nsTableColFrame::nsTableColFrame(nsStyleContext* aContext)
-  : nsSplittableFrame(aContext, LayoutFrameType::TableCol)
+  : nsSplittableFrame(aContext, kClassID, LayoutFrameType::TableCol)
   , mMinCoord(0)
   , mPrefCoord(0)
   , mSpanMinCoord(0)
diff --git a/layout/tables/nsTableColGroupFrame.h b/layout/tables/nsTableColGroupFrame.h
index dc98f7c4622d..ee4bf97421f9 100644
--- a/layout/tables/nsTableColGroupFrame.h
+++ b/layout/tables/nsTableColGroupFrame.h
@@ -221,7 +221,7 @@ protected:
 };
 
 inline nsTableColGroupFrame::nsTableColGroupFrame(nsStyleContext* aContext)
-  : nsContainerFrame(aContext, mozilla::LayoutFrameType::TableColGroup)
+  : nsContainerFrame(aContext, kClassID, mozilla::LayoutFrameType::TableColGroup)
   , mColCount(0)
   , mStartColIndex(0)
 {
diff --git a/layout/tables/nsTableFrame.cpp b/layout/tables/nsTableFrame.cpp
index 4bd33e3f26dc..a90391ac891b 100644
--- a/layout/tables/nsTableFrame.cpp
+++ b/layout/tables/nsTableFrame.cpp
@@ -146,8 +146,8 @@ nsTableFrame::GetParentStyleContext(nsIFrame** aProviderFrame) const
   return GetParent()->DoGetParentStyleContext(aProviderFrame);
 }
 
-nsTableFrame::nsTableFrame(nsStyleContext* aContext)
-  : nsContainerFrame(aContext, LayoutFrameType::Table)
+nsTableFrame::nsTableFrame(nsStyleContext* aContext, ClassID aID)
+  : nsContainerFrame(aContext, aID, LayoutFrameType::Table)
   , mCellMap(nullptr)
   , mTableLayoutStrategy(nullptr)
 {
diff --git a/layout/tables/nsTableFrame.h b/layout/tables/nsTableFrame.h
index 5e0840cb4364..c1450093a354 100644
--- a/layout/tables/nsTableFrame.h
+++ b/layout/tables/nsTableFrame.h
@@ -603,7 +603,7 @@ protected:
   /** protected constructor.
     * @see NewFrame
     */
-  explicit nsTableFrame(nsStyleContext* aContext);
+  explicit nsTableFrame(nsStyleContext* aContext, ClassID aID = kClassID);
 
   /** destructor, responsible for mColumnLayoutData */
   virtual ~nsTableFrame();
diff --git a/layout/tables/nsTableRowFrame.cpp b/layout/tables/nsTableRowFrame.cpp
index 9dead7481d1b..5b5fe89dda84 100644
--- a/layout/tables/nsTableRowFrame.cpp
+++ b/layout/tables/nsTableRowFrame.cpp
@@ -129,8 +129,8 @@ NS_QUERYFRAME_HEAD(nsTableRowFrame)
   NS_QUERYFRAME_ENTRY(nsTableRowFrame)
 NS_QUERYFRAME_TAIL_INHERITING(nsContainerFrame)
 
-nsTableRowFrame::nsTableRowFrame(nsStyleContext* aContext)
-  : nsContainerFrame(aContext, LayoutFrameType::TableRow)
+nsTableRowFrame::nsTableRowFrame(nsStyleContext* aContext, ClassID aID)
+  : nsContainerFrame(aContext, aID, LayoutFrameType::TableRow)
   , mContentBSize(0)
   , mStylePctBSize(0)
   , mStyleFixedBSize(0)
diff --git a/layout/tables/nsTableRowFrame.h b/layout/tables/nsTableRowFrame.h
index 884b5fecc07c..2bf54b384afa 100644
--- a/layout/tables/nsTableRowFrame.h
+++ b/layout/tables/nsTableRowFrame.h
@@ -254,7 +254,7 @@ protected:
   /** protected constructor.
     * @see NewFrame
     */
-  explicit nsTableRowFrame(nsStyleContext *aContext);
+  explicit nsTableRowFrame(nsStyleContext* aContext, ClassID aID = kClassID);
 
   void InitChildReflowInput(nsPresContext&              aPresContext,
                             const mozilla::LogicalSize& aAvailSize,
diff --git a/layout/tables/nsTableRowGroupFrame.cpp b/layout/tables/nsTableRowGroupFrame.cpp
index 121bd64ccfcb..5d13e0d54cd0 100644
--- a/layout/tables/nsTableRowGroupFrame.cpp
+++ b/layout/tables/nsTableRowGroupFrame.cpp
@@ -54,7 +54,7 @@ struct TableRowGroupReflowInput {
 } // namespace mozilla
 
 nsTableRowGroupFrame::nsTableRowGroupFrame(nsStyleContext* aContext)
-  : nsContainerFrame(aContext, LayoutFrameType::TableRowGroup)
+  : nsContainerFrame(aContext, kClassID, LayoutFrameType::TableRowGroup)
 {
   SetRepeatable(false);
 }
diff --git a/layout/tables/nsTableWrapperFrame.cpp b/layout/tables/nsTableWrapperFrame.cpp
index 0cdfcde1ec92..307e6bccdfdb 100644
--- a/layout/tables/nsTableWrapperFrame.cpp
+++ b/layout/tables/nsTableWrapperFrame.cpp
@@ -42,8 +42,8 @@ nsTableWrapperFrame::GetLogicalBaseline(WritingMode aWritingMode) const
          kid->BStart(aWritingMode, mRect.Size());
 }
 
-nsTableWrapperFrame::nsTableWrapperFrame(nsStyleContext* aContext)
-  : nsContainerFrame(aContext, LayoutFrameType::TableWrapper)
+nsTableWrapperFrame::nsTableWrapperFrame(nsStyleContext* aContext, ClassID aID)
+  : nsContainerFrame(aContext, aID, LayoutFrameType::TableWrapper)
 {
 }
 
diff --git a/layout/tables/nsTableWrapperFrame.h b/layout/tables/nsTableWrapperFrame.h
index 8bcc2745c5b0..b9720a74a20a 100644
--- a/layout/tables/nsTableWrapperFrame.h
+++ b/layout/tables/nsTableWrapperFrame.h
@@ -196,7 +196,7 @@ public:
 
 protected:
 
-  explicit nsTableWrapperFrame(nsStyleContext* aContext);
+  explicit nsTableWrapperFrame(nsStyleContext* aContext, ClassID aID = kClassID);
   virtual ~nsTableWrapperFrame();
 
   void InitChildReflowInput(nsPresContext&     aPresContext,
diff --git a/layout/xul/grid/nsGridRowGroupFrame.h b/layout/xul/grid/nsGridRowGroupFrame.h
index 15f4a79e665c..01300b6399cc 100644
--- a/layout/xul/grid/nsGridRowGroupFrame.h
+++ b/layout/xul/grid/nsGridRowGroupFrame.h
@@ -37,7 +37,7 @@ public:
 
   nsGridRowGroupFrame(nsStyleContext* aContext,
                       nsBoxLayout* aLayoutManager):
-    nsBoxFrame(aContext, false, aLayoutManager) {}
+    nsBoxFrame(aContext, kClassID, false, aLayoutManager) {}
 
   virtual nscoord GetXULFlex() override;
 
diff --git a/layout/xul/grid/nsGridRowLeafFrame.h b/layout/xul/grid/nsGridRowLeafFrame.h
index 1636afa24ba4..3a18c96dd444 100644
--- a/layout/xul/grid/nsGridRowLeafFrame.h
+++ b/layout/xul/grid/nsGridRowLeafFrame.h
@@ -41,8 +41,9 @@ public:
 
   nsGridRowLeafFrame(nsStyleContext* aContext,
                      bool aIsRoot,
-                     nsBoxLayout* aLayoutManager):
-    nsBoxFrame(aContext, aIsRoot, aLayoutManager) {}
+                     nsBoxLayout* aLayoutManager,
+                     ClassID aID = kClassID) :
+    nsBoxFrame(aContext, aID, aIsRoot, aLayoutManager) {}
 
   virtual nsresult GetXULBorderAndPadding(nsMargin& aBorderAndPadding) override;
 
diff --git a/layout/xul/nsBox.cpp b/layout/xul/nsBox.cpp
index 36661b060ce0..9d76c1e3ad13 100644
--- a/layout/xul/nsBox.cpp
+++ b/layout/xul/nsBox.cpp
@@ -176,8 +176,8 @@ nsBox::EndXULLayout(nsBoxLayoutState& aState)
 bool nsBox::gGotTheme = false;
 nsITheme* nsBox::gTheme = nullptr;
 
-nsBox::nsBox(LayoutFrameType aType)
-  : nsIFrame(aType)
+nsBox::nsBox(ClassID aID, LayoutFrameType aType)
+  : nsIFrame(aID, aType)
 {
   MOZ_COUNT_CTOR(nsBox);
   //mX = 0;
diff --git a/layout/xul/nsBox.h b/layout/xul/nsBox.h
index 0a1ec0f3976f..3d47305294bc 100644
--- a/layout/xul/nsBox.h
+++ b/layout/xul/nsBox.h
@@ -50,7 +50,7 @@ public:
   void PropagateDebug(nsBoxLayoutState& aState);
 #endif
 
-  explicit nsBox(mozilla::LayoutFrameType);
+  nsBox(ClassID aID, mozilla::LayoutFrameType);
   virtual ~nsBox();
 
   /**
diff --git a/layout/xul/nsBoxFrame.cpp b/layout/xul/nsBoxFrame.cpp
index 95ae86266f2a..3fa6bfbf9a3c 100644
--- a/layout/xul/nsBoxFrame.cpp
+++ b/layout/xul/nsBoxFrame.cpp
@@ -98,7 +98,8 @@ nsIFrame* nsBoxFrame::mDebugChild = nullptr;
 nsIFrame*
 NS_NewBoxFrame(nsIPresShell* aPresShell, nsStyleContext* aContext, bool aIsRoot, nsBoxLayout* aLayoutManager)
 {
-  return new (aPresShell) nsBoxFrame(aContext, aIsRoot, aLayoutManager);
+  return new (aPresShell) nsBoxFrame(aContext, nsBoxFrame::kClassID,
+                                     aIsRoot, aLayoutManager);
 }
 
 nsIFrame*
@@ -116,10 +117,11 @@ NS_QUERYFRAME_TAIL_INHERITING(nsContainerFrame)
 #endif
 
 nsBoxFrame::nsBoxFrame(nsStyleContext* aContext,
+                       ClassID aID,
                        LayoutFrameType aType,
                        bool aIsRoot,
                        nsBoxLayout* aLayoutManager)
-  : nsContainerFrame(aContext, aType)
+  : nsContainerFrame(aContext, aID, aType)
   , mFlex(0)
   , mAscent(0)
 {
diff --git a/layout/xul/nsBoxFrame.h b/layout/xul/nsBoxFrame.h
index 492970c68058..e7e6d92053de 100644
--- a/layout/xul/nsBoxFrame.h
+++ b/layout/xul/nsBoxFrame.h
@@ -141,9 +141,10 @@ public:
   virtual ~nsBoxFrame();
 
   explicit nsBoxFrame(nsStyleContext* aContext,
+                      ClassID aID = kClassID,
                       bool aIsRoot = false,
                       nsBoxLayout* aLayoutManager = nullptr)
-    : nsBoxFrame(aContext,
+    : nsBoxFrame(aContext, aID,
                  mozilla::LayoutFrameType::Box,
                  aIsRoot,
                  aLayoutManager)
@@ -184,6 +185,7 @@ public:
 
 protected:
   nsBoxFrame(nsStyleContext* aContext,
+             ClassID aID,
              mozilla::LayoutFrameType aType,
              bool aIsRoot = false,
              nsBoxLayout* aLayoutManager = nullptr);
diff --git a/layout/xul/nsButtonBoxFrame.cpp b/layout/xul/nsButtonBoxFrame.cpp
index 7a3ee9a6e037..124e39ad84a8 100644
--- a/layout/xul/nsButtonBoxFrame.cpp
+++ b/layout/xul/nsButtonBoxFrame.cpp
@@ -59,8 +59,8 @@ NS_NewButtonBoxFrame (nsIPresShell* aPresShell, nsStyleContext* aContext)
 
 NS_IMPL_FRAMEARENA_HELPERS(nsButtonBoxFrame)
 
-nsButtonBoxFrame::nsButtonBoxFrame(nsStyleContext* aContext) :
-  nsBoxFrame(aContext, false),
+nsButtonBoxFrame::nsButtonBoxFrame(nsStyleContext* aContext, ClassID aID) :
+  nsBoxFrame(aContext, aID, false),
   mButtonBoxListener(nullptr),
   mIsHandlingKeyEvent(false)
 {
diff --git a/layout/xul/nsButtonBoxFrame.h b/layout/xul/nsButtonBoxFrame.h
index 9ccc9587b9fc..e5a44f0d70ad 100644
--- a/layout/xul/nsButtonBoxFrame.h
+++ b/layout/xul/nsButtonBoxFrame.h
@@ -16,7 +16,7 @@ public:
 
   friend nsIFrame* NS_NewButtonBoxFrame(nsIPresShell* aPresShell);
 
-  explicit nsButtonBoxFrame(nsStyleContext* aContext);
+  explicit nsButtonBoxFrame(nsStyleContext* aContext, ClassID = kClassID);
 
   virtual void Init(nsIContent*       aContent,
                     nsContainerFrame* aParent,
diff --git a/layout/xul/nsDeckFrame.cpp b/layout/xul/nsDeckFrame.cpp
index 026799c3da32..1719d8c1417f 100644
--- a/layout/xul/nsDeckFrame.cpp
+++ b/layout/xul/nsDeckFrame.cpp
@@ -44,7 +44,7 @@ NS_QUERYFRAME_HEAD(nsDeckFrame)
 NS_QUERYFRAME_TAIL_INHERITING(nsBoxFrame)
 
 nsDeckFrame::nsDeckFrame(nsStyleContext* aContext)
-  : nsBoxFrame(aContext, LayoutFrameType::Deck)
+  : nsBoxFrame(aContext, kClassID, LayoutFrameType::Deck)
   , mIndex(0)
 {
   nsCOMPtr<nsBoxLayout> layout;
diff --git a/layout/xul/nsDocElementBoxFrame.cpp b/layout/xul/nsDocElementBoxFrame.cpp
index a846bf87a1f3..525772a8d670 100644
--- a/layout/xul/nsDocElementBoxFrame.cpp
+++ b/layout/xul/nsDocElementBoxFrame.cpp
@@ -36,7 +36,7 @@ public:
                                   nsStyleContext* aContext);
 
   explicit nsDocElementBoxFrame(nsStyleContext* aContext)
-    :nsBoxFrame(aContext, true) {}
+    :nsBoxFrame(aContext, kClassID, true) {}
 
   NS_DECL_QUERYFRAME
   NS_DECL_FRAMEARENA_HELPERS(nsDocElementBoxFrame)
diff --git a/layout/xul/nsGroupBoxFrame.cpp b/layout/xul/nsGroupBoxFrame.cpp
index 51c5323eb198..da9305410542 100644
--- a/layout/xul/nsGroupBoxFrame.cpp
+++ b/layout/xul/nsGroupBoxFrame.cpp
@@ -24,7 +24,7 @@ public:
   NS_DECL_FRAMEARENA_HELPERS(nsGroupBoxFrame)
 
   explicit nsGroupBoxFrame(nsStyleContext* aContext):
-    nsBoxFrame(aContext) {}
+    nsBoxFrame(aContext, kClassID) {}
 
   virtual nsresult GetXULBorderAndPadding(nsMargin& aBorderAndPadding) override;
 
diff --git a/layout/xul/nsImageBoxFrame.cpp b/layout/xul/nsImageBoxFrame.cpp
index 9ac541400f71..62e106bdc43f 100644
--- a/layout/xul/nsImageBoxFrame.cpp
+++ b/layout/xul/nsImageBoxFrame.cpp
@@ -151,7 +151,7 @@ nsImageBoxFrame::AttributeChanged(int32_t aNameSpaceID,
 }
 
 nsImageBoxFrame::nsImageBoxFrame(nsStyleContext* aContext)
-  : nsLeafBoxFrame(aContext, LayoutFrameType::ImageBox)
+  : nsLeafBoxFrame(aContext, kClassID, LayoutFrameType::ImageBox)
   , mIntrinsicSize(0, 0)
   , mLoadFlags(nsIRequest::LOAD_NORMAL)
   , mRequestRegistered(false)
diff --git a/layout/xul/nsLeafBoxFrame.cpp b/layout/xul/nsLeafBoxFrame.cpp
index 7f9459a8fec7..85274d39dfc4 100644
--- a/layout/xul/nsLeafBoxFrame.cpp
+++ b/layout/xul/nsLeafBoxFrame.cpp
@@ -40,8 +40,8 @@ NS_NewLeafBoxFrame (nsIPresShell* aPresShell, nsStyleContext* aContext)
 
 NS_IMPL_FRAMEARENA_HELPERS(nsLeafBoxFrame)
 
-nsLeafBoxFrame::nsLeafBoxFrame(nsStyleContext* aContext, LayoutFrameType aType)
-  : nsLeafFrame(aContext, aType)
+nsLeafBoxFrame::nsLeafBoxFrame(nsStyleContext* aContext, ClassID aID, LayoutFrameType aType)
+  : nsLeafFrame(aContext, aID, aType)
 {
 }
 
diff --git a/layout/xul/nsLeafBoxFrame.h b/layout/xul/nsLeafBoxFrame.h
index 11bce4cc31f1..c557050762d5 100644
--- a/layout/xul/nsLeafBoxFrame.h
+++ b/layout/xul/nsLeafBoxFrame.h
@@ -82,11 +82,11 @@ protected:
 
   virtual nscoord GetIntrinsicISize() override;
 
-  explicit nsLeafBoxFrame(nsStyleContext* aContext)
-    : nsLeafBoxFrame(aContext, mozilla::LayoutFrameType::LeafBox)
+  explicit nsLeafBoxFrame(nsStyleContext* aContext, ClassID aID = kClassID)
+    : nsLeafBoxFrame(aContext, aID, mozilla::LayoutFrameType::LeafBox)
   {}
 
-  nsLeafBoxFrame(nsStyleContext* aContext, mozilla::LayoutFrameType aType);
+  nsLeafBoxFrame(nsStyleContext* aContext, ClassID aID, mozilla::LayoutFrameType aType);
 
 private:
 
diff --git a/layout/xul/nsListBoxBodyFrame.cpp b/layout/xul/nsListBoxBodyFrame.cpp
index 620f37e21dd3..9a6a2ea47957 100644
--- a/layout/xul/nsListBoxBodyFrame.cpp
+++ b/layout/xul/nsListBoxBodyFrame.cpp
@@ -151,7 +151,7 @@ nsListScrollSmoother::Stop()
 
 nsListBoxBodyFrame::nsListBoxBodyFrame(nsStyleContext* aContext,
                                        nsBoxLayout* aLayoutManager)
-  : nsBoxFrame(aContext, false, aLayoutManager),
+  : nsBoxFrame(aContext, kClassID, false, aLayoutManager),
     mTopFrame(nullptr),
     mBottomFrame(nullptr),
     mLinkupFrame(nullptr),
diff --git a/layout/xul/nsListItemFrame.cpp b/layout/xul/nsListItemFrame.cpp
index 1776f1b6cb2b..bb1075fed60b 100644
--- a/layout/xul/nsListItemFrame.cpp
+++ b/layout/xul/nsListItemFrame.cpp
@@ -17,7 +17,7 @@
 nsListItemFrame::nsListItemFrame(nsStyleContext* aContext,
                                  bool aIsRoot,
                                  nsBoxLayout* aLayoutManager)
-  : nsGridRowLeafFrame(aContext, aIsRoot, aLayoutManager) 
+  : nsGridRowLeafFrame(aContext, aIsRoot, aLayoutManager, kClassID) 
 {
 }
 
diff --git a/layout/xul/nsMenuBarFrame.cpp b/layout/xul/nsMenuBarFrame.cpp
index eeb72d28c8fb..1687128cb7bd 100644
--- a/layout/xul/nsMenuBarFrame.cpp
+++ b/layout/xul/nsMenuBarFrame.cpp
@@ -51,7 +51,7 @@ NS_QUERYFRAME_TAIL_INHERITING(nsBoxFrame)
 // nsMenuBarFrame cntr
 //
 nsMenuBarFrame::nsMenuBarFrame(nsStyleContext* aContext)
-  : nsBoxFrame(aContext)
+  : nsBoxFrame(aContext, kClassID)
   , mStayActive(false)
   , mIsActive(false)
   , mActiveByKeyboard(false)
diff --git a/layout/xul/nsMenuFrame.cpp b/layout/xul/nsMenuFrame.cpp
index 059ac5ef149c..72a8c76d0ed6 100644
--- a/layout/xul/nsMenuFrame.cpp
+++ b/layout/xul/nsMenuFrame.cpp
@@ -170,7 +170,7 @@ NS_QUERYFRAME_HEAD(nsMenuFrame)
 NS_QUERYFRAME_TAIL_INHERITING(nsBoxFrame)
 
 nsMenuFrame::nsMenuFrame(nsStyleContext* aContext)
-  : nsBoxFrame(aContext, LayoutFrameType::Menu)
+  : nsBoxFrame(aContext, kClassID, LayoutFrameType::Menu)
   , mIsMenu(false)
   , mChecked(false)
   , mIgnoreAccelTextChange(false)
diff --git a/layout/xul/nsMenuPopupFrame.cpp b/layout/xul/nsMenuPopupFrame.cpp
index bf882e03ae36..ac8877258186 100644
--- a/layout/xul/nsMenuPopupFrame.cpp
+++ b/layout/xul/nsMenuPopupFrame.cpp
@@ -95,7 +95,7 @@ NS_QUERYFRAME_TAIL_INHERITING(nsBoxFrame)
 // nsMenuPopupFrame ctor
 //
 nsMenuPopupFrame::nsMenuPopupFrame(nsStyleContext* aContext)
-  : nsBoxFrame(aContext, LayoutFrameType::MenuPopup)
+  : nsBoxFrame(aContext, kClassID, LayoutFrameType::MenuPopup)
   , mCurrentMenu(nullptr)
   , mView(nullptr)
   , mPrefSize(-1, -1)
diff --git a/layout/xul/nsPopupSetFrame.h b/layout/xul/nsPopupSetFrame.h
index 2950502ec674..5449c20ed7ae 100644
--- a/layout/xul/nsPopupSetFrame.h
+++ b/layout/xul/nsPopupSetFrame.h
@@ -19,7 +19,7 @@ public:
   NS_DECL_FRAMEARENA_HELPERS(nsPopupSetFrame)
 
   explicit nsPopupSetFrame(nsStyleContext* aContext)
-    : nsBoxFrame(aContext, mozilla::LayoutFrameType::PopupSet)
+    : nsBoxFrame(aContext, kClassID, mozilla::LayoutFrameType::PopupSet)
   {}
 
   ~nsPopupSetFrame() {}
diff --git a/layout/xul/nsProgressMeterFrame.h b/layout/xul/nsProgressMeterFrame.h
index e19c903fa40f..0f097aea723a 100644
--- a/layout/xul/nsProgressMeterFrame.h
+++ b/layout/xul/nsProgressMeterFrame.h
@@ -39,7 +39,7 @@ public:
 
 protected:
   explicit nsProgressMeterFrame(nsStyleContext* aContext) :
-    nsBoxFrame(aContext), mNeedsReflowCallback(true) {}
+    nsBoxFrame(aContext, kClassID), mNeedsReflowCallback(true) {}
   virtual ~nsProgressMeterFrame();
 
   bool mNeedsReflowCallback;
diff --git a/layout/xul/nsResizerFrame.cpp b/layout/xul/nsResizerFrame.cpp
index e825473857e9..2be942ffb109 100644
--- a/layout/xul/nsResizerFrame.cpp
+++ b/layout/xul/nsResizerFrame.cpp
@@ -46,7 +46,7 @@ NS_NewResizerFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
 NS_IMPL_FRAMEARENA_HELPERS(nsResizerFrame)
 
 nsResizerFrame::nsResizerFrame(nsStyleContext* aContext)
-:nsTitleBarFrame(aContext)
+  : nsTitleBarFrame(aContext, kClassID)
 {
 }
 
diff --git a/layout/xul/nsRootBoxFrame.cpp b/layout/xul/nsRootBoxFrame.cpp
index 55cf439c7111..655aee3679f5 100644
--- a/layout/xul/nsRootBoxFrame.cpp
+++ b/layout/xul/nsRootBoxFrame.cpp
@@ -108,7 +108,7 @@ NS_NewRootBoxFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
 NS_IMPL_FRAMEARENA_HELPERS(nsRootBoxFrame)
 
 nsRootBoxFrame::nsRootBoxFrame(nsStyleContext* aContext)
-  : nsBoxFrame(aContext, LayoutFrameType::Root, true)
+  : nsBoxFrame(aContext, kClassID, LayoutFrameType::Root, true)
   , mPopupSetFrame(nullptr)
   , mDefaultTooltip(nullptr)
 {
diff --git a/layout/xul/nsScrollBoxFrame.cpp b/layout/xul/nsScrollBoxFrame.cpp
index 1dea94d036b6..7e3ad897bef2 100644
--- a/layout/xul/nsScrollBoxFrame.cpp
+++ b/layout/xul/nsScrollBoxFrame.cpp
@@ -42,7 +42,7 @@ public:
 
 protected:
   explicit nsAutoRepeatBoxFrame(nsStyleContext* aContext):
-    nsButtonBoxFrame(aContext) {}
+    nsButtonBoxFrame(aContext, kClassID) {}
   
   void StartRepeat() {
     if (IsActivatedOnHover()) {
diff --git a/layout/xul/nsScrollbarButtonFrame.h b/layout/xul/nsScrollbarButtonFrame.h
index 4abee4c47f00..e6bac231b598 100644
--- a/layout/xul/nsScrollbarButtonFrame.h
+++ b/layout/xul/nsScrollbarButtonFrame.h
@@ -24,7 +24,7 @@ public:
   NS_DECL_FRAMEARENA_HELPERS(nsScrollbarButtonFrame)
 
   explicit nsScrollbarButtonFrame(nsStyleContext* aContext):
-    nsButtonBoxFrame(aContext), mCursorOnThis(false) {}
+    nsButtonBoxFrame(aContext, kClassID), mCursorOnThis(false) {}
 
   // Overrides
   virtual void DestroyFrom(nsIFrame* aDestructRoot) override;
diff --git a/layout/xul/nsScrollbarFrame.h b/layout/xul/nsScrollbarFrame.h
index b167bc611f3b..758fb612da22 100644
--- a/layout/xul/nsScrollbarFrame.h
+++ b/layout/xul/nsScrollbarFrame.h
@@ -21,7 +21,7 @@ class nsScrollbarFrame final : public nsBoxFrame
 {
 public:
   explicit nsScrollbarFrame(nsStyleContext* aContext)
-    : nsBoxFrame(aContext, mozilla::LayoutFrameType::Scrollbar)
+    : nsBoxFrame(aContext, kClassID, mozilla::LayoutFrameType::Scrollbar)
     , mIncrement(0)
     , mSmoothScroll(false)
     , mScrollbarMediator(nullptr)
diff --git a/layout/xul/nsSliderFrame.cpp b/layout/xul/nsSliderFrame.cpp
index 970e3129ef59..f57ca27a96ad 100644
--- a/layout/xul/nsSliderFrame.cpp
+++ b/layout/xul/nsSliderFrame.cpp
@@ -84,7 +84,7 @@ NS_QUERYFRAME_HEAD(nsSliderFrame)
 NS_QUERYFRAME_TAIL_INHERITING(nsBoxFrame)
 
 nsSliderFrame::nsSliderFrame(nsStyleContext* aContext)
-  : nsBoxFrame(aContext, LayoutFrameType::Slider)
+  : nsBoxFrame(aContext, kClassID, LayoutFrameType::Slider)
   , mRatio(0.0f)
   , mDragStart(0)
   , mThumbStart(0)
diff --git a/layout/xul/nsSplitterFrame.cpp b/layout/xul/nsSplitterFrame.cpp
index a1abccee4657..de14a35124cc 100644
--- a/layout/xul/nsSplitterFrame.cpp
+++ b/layout/xul/nsSplitterFrame.cpp
@@ -203,7 +203,7 @@ NS_NewSplitterFrame (nsIPresShell* aPresShell, nsStyleContext* aContext)
 NS_IMPL_FRAMEARENA_HELPERS(nsSplitterFrame)
 
 nsSplitterFrame::nsSplitterFrame(nsStyleContext* aContext)
-: nsBoxFrame(aContext),
+: nsBoxFrame(aContext, kClassID),
   mInner(0)
 {
 }
diff --git a/layout/xul/nsStackFrame.cpp b/layout/xul/nsStackFrame.cpp
index 437d558f910c..e75ae050de75 100644
--- a/layout/xul/nsStackFrame.cpp
+++ b/layout/xul/nsStackFrame.cpp
@@ -30,7 +30,7 @@ NS_NewStackFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
 NS_IMPL_FRAMEARENA_HELPERS(nsStackFrame)
 
 nsStackFrame::nsStackFrame(nsStyleContext* aContext):
-  nsBoxFrame(aContext)
+  nsBoxFrame(aContext, kClassID)
 {
   nsCOMPtr<nsBoxLayout> layout;
   NS_NewStackLayout(layout);
diff --git a/layout/xul/nsTextBoxFrame.cpp b/layout/xul/nsTextBoxFrame.cpp
index 263a3253ee34..923dbfa26b65 100644
--- a/layout/xul/nsTextBoxFrame.cpp
+++ b/layout/xul/nsTextBoxFrame.cpp
@@ -100,7 +100,7 @@ nsTextBoxFrame::AttributeChanged(int32_t         aNameSpaceID,
 }
 
 nsTextBoxFrame::nsTextBoxFrame(nsStyleContext* aContext)
-  : nsLeafBoxFrame(aContext)
+  : nsLeafBoxFrame(aContext, kClassID)
   , mAccessKeyInfo(nullptr)
   , mCropType(CropRight)
   , mAscent(0)
diff --git a/layout/xul/nsTitleBarFrame.cpp b/layout/xul/nsTitleBarFrame.cpp
index 2792403dcc02..c0ca37df0258 100644
--- a/layout/xul/nsTitleBarFrame.cpp
+++ b/layout/xul/nsTitleBarFrame.cpp
@@ -33,8 +33,8 @@ NS_NewTitleBarFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
 
 NS_IMPL_FRAMEARENA_HELPERS(nsTitleBarFrame)
 
-nsTitleBarFrame::nsTitleBarFrame(nsStyleContext* aContext)
-:nsBoxFrame(aContext, false)
+nsTitleBarFrame::nsTitleBarFrame(nsStyleContext* aContext, ClassID aID)
+  : nsBoxFrame(aContext, aID, false)
 {
   mTrackingMouseMove = false;
   UpdateMouseThrough();
diff --git a/layout/xul/nsTitleBarFrame.h b/layout/xul/nsTitleBarFrame.h
index e4d6f5fc1e62..975ee2e533d4 100644
--- a/layout/xul/nsTitleBarFrame.h
+++ b/layout/xul/nsTitleBarFrame.h
@@ -16,7 +16,7 @@ public:
 
   friend nsIFrame* NS_NewTitleBarFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);  
 
-  explicit nsTitleBarFrame(nsStyleContext* aContext);
+  explicit nsTitleBarFrame(nsStyleContext* aContext, ClassID = kClassID);
 
   virtual void BuildDisplayListForChildren(nsDisplayListBuilder*   aBuilder,
                                            const nsRect&           aDirtyRect,
diff --git a/layout/xul/nsXULLabelFrame.h b/layout/xul/nsXULLabelFrame.h
index 591ef4be97d9..880517d97ccd 100644
--- a/layout/xul/nsXULLabelFrame.h
+++ b/layout/xul/nsXULLabelFrame.h
@@ -40,7 +40,7 @@ public:
 
 protected:
   explicit nsXULLabelFrame(nsStyleContext* aContext)
-    : nsBlockFrame(aContext, mozilla::LayoutFrameType::XULLabel)
+    : nsBlockFrame(aContext, kClassID, mozilla::LayoutFrameType::XULLabel)
   {}
 
   nsresult RegUnregAccessKey(bool aDoReg);
diff --git a/layout/xul/tree/nsTreeBodyFrame.cpp b/layout/xul/tree/nsTreeBodyFrame.cpp
index 00a068cd779b..9b74252ce7da 100644
--- a/layout/xul/tree/nsTreeBodyFrame.cpp
+++ b/layout/xul/tree/nsTreeBodyFrame.cpp
@@ -114,7 +114,7 @@ NS_QUERYFRAME_TAIL_INHERITING(nsLeafBoxFrame)
 
 // Constructor
 nsTreeBodyFrame::nsTreeBodyFrame(nsStyleContext* aContext)
-:nsLeafBoxFrame(aContext),
+:nsLeafBoxFrame(aContext, kClassID),
  mSlots(nullptr),
  mImageCache(),
  mTopRowIndex(0),
diff --git a/layout/xul/tree/nsTreeColFrame.h b/layout/xul/tree/nsTreeColFrame.h
index 12f927bd1998..95e8e8dadf32 100644
--- a/layout/xul/tree/nsTreeColFrame.h
+++ b/layout/xul/tree/nsTreeColFrame.h
@@ -17,7 +17,7 @@ public:
   NS_DECL_FRAMEARENA_HELPERS(nsTreeColFrame)
 
   explicit nsTreeColFrame(nsStyleContext* aContext):
-    nsBoxFrame(aContext) {}
+    nsBoxFrame(aContext, kClassID) {}
 
   virtual void Init(nsIContent*       aContent,
                     nsContainerFrame* aParent,