Bug 1475033 part 1 - Rename nsChangeHint_CSSOverflowChange to nsChangeHint_ScrollbarChange. r=heycam

Prepare for scrollbar-width which should trigger the same kind of change.

MozReview-Commit-ID: 1n9Y9bobBkJ

--HG--
extra : rebase_source : 520b78dec4daca5050e0cc7fff4ec68fa36663c5

layout/base/RestyleManager.cpp

@@ -599,7 +599,7 @@ RestyleManager::ChangeHintToString(nsChangeHint aHint)
     "NeutralChange", "InvalidateRenderingObservers",
     "ReflowChangesSizeOrPosition", "UpdateComputedBSize",
     "UpdateUsesOpacity", "UpdateBackgroundPosition",
-    "AddOrRemoveTransform", "CSSOverflowChange",
+    "AddOrRemoveTransform", "ScrollbarChange",
     "UpdateWidgetProperties", "UpdateTableCellSpans",
     "VisibilityChange"
   };
@@ -1355,11 +1355,11 @@ RestyleManager::ProcessRestyledFrames(nsStyleChangeList& aChangeList)
   nsPresContext* presContext = PresContext();
   nsCSSFrameConstructor* frameConstructor = presContext->FrameConstructor();
 
-  // Handle nsChangeHint_CSSOverflowChange, by either updating the
+  // Handle nsChangeHint_ScrollbarChange, by either updating the
   // scrollbars on the viewport, or upgrading the change hint to frame-reconstruct.
   for (nsStyleChangeData& data : aChangeList) {
-    if (data.mHint & nsChangeHint_CSSOverflowChange) {
-      data.mHint &= ~nsChangeHint_CSSOverflowChange;
+    if (data.mHint & nsChangeHint_ScrollbarChange) {
+      data.mHint &= ~nsChangeHint_ScrollbarChange;
       bool doReconstruct = true; // assume the worst
 
       // Only bother with this if we're html/body, since:

layout/base/nsChangeHint.h

@@ -222,14 +222,16 @@ enum nsChangeHint : uint32_t {
   nsChangeHint_AddOrRemoveTransform = 1 << 27,
 
   /**
-   * Indicates that the overflow-x and/or overflow-y property changed.
+   * Indicates that the presence of scrollbars might have changed.
+   *
+   * This happens when at least one of overflow-{x,y} properties changed.
    *
    * In most cases, this is equivalent to nsChangeHint_ReconstructFrame. But
    * in some special cases where the change is really targeting the viewport's
    * scrollframe, this is instead equivalent to nsChangeHint_AllReflowHints
    * (because the viewport always has an associated scrollframe).
    */
-  nsChangeHint_CSSOverflowChange = 1 << 28,
+  nsChangeHint_ScrollbarChange = 1 << 28,
 
   /**
    * Indicates that nsIFrame::UpdateWidgetProperties needs to be called.
@@ -356,7 +358,7 @@ inline nsChangeHint operator^=(nsChangeHint& aLeft, nsChangeHint aRight)
 #define nsChangeHint_Hints_NeverHandledForDescendants (    \
   nsChangeHint_BorderStyleNoneChange |                     \
   nsChangeHint_ChildrenOnlyTransform |                     \
-  nsChangeHint_CSSOverflowChange |                         \
+  nsChangeHint_ScrollbarChange |                           \
   nsChangeHint_InvalidateRenderingObservers |              \
   nsChangeHint_RecomputePosition |                         \
   nsChangeHint_UpdateBackgroundPosition |                  \

layout/style/nsStyleStruct.cpp

@@ -3771,7 +3771,7 @@ nsStyleDisplay::CalcDifference(const nsStyleDisplay& aNewData) const
 
   if (mOverflowX != aNewData.mOverflowX
       || mOverflowY != aNewData.mOverflowY) {
-    hint |= nsChangeHint_CSSOverflowChange;
+    hint |= nsChangeHint_ScrollbarChange;
   }
 
   /* Note: When mScrollBehavior, mScrollSnapTypeX, mScrollSnapTypeY,
@@ -3808,7 +3808,7 @@ nsStyleDisplay::CalcDifference(const nsStyleDisplay& aNewData) const
       // XXX What is the minimum hint to ensure mShapeInfo is regenerated in
       // the next reflow?
       hint |= nsChangeHint_ReflowHintsForFloatAreaChange |
-              nsChangeHint_CSSOverflowChange;
+              nsChangeHint_ScrollbarChange;
     } else {
       // shape-outside or shape-margin or shape-image-threshold changed,
       // but we don't need to reflow because we're not floating.