diff --git a/content/base/src/nsObjectLoadingContent.cpp b/content/base/src/nsObjectLoadingContent.cpp
index a763f5a6e3e5..e642bb12b09d 100644
--- a/content/base/src/nsObjectLoadingContent.cpp
+++ b/content/base/src/nsObjectLoadingContent.cpp
@@ -82,6 +82,13 @@
 #include "mozilla/dom/BindingUtils.h"
 #include "mozilla/Telemetry.h"
 
+#ifdef XP_WIN
+// Thanks so much, Microsoft! :(
+#ifdef CreateEvent
+#undef CreateEvent
+#endif
+#endif // XP_WIN
+
 static NS_DEFINE_CID(kAppShellCID, NS_APPSHELL_CID);
 
 using namespace mozilla;
diff --git a/content/html/content/src/HTMLMediaElement.cpp b/content/html/content/src/HTMLMediaElement.cpp
index 39bf5d679ec7..7de7d8586d7c 100644
--- a/content/html/content/src/HTMLMediaElement.cpp
+++ b/content/html/content/src/HTMLMediaElement.cpp
@@ -76,6 +76,7 @@
 
 #include "ImageContainer.h"
 #include "nsIPowerManagerService.h"
+#include "nsRange.h"
 #include <algorithm>
 
 #ifdef PR_LOGGING
diff --git a/layout/generic/ScrollbarActivity.cpp b/layout/generic/ScrollbarActivity.cpp
index ca411672da50..d88a6dbcb89c 100644
--- a/layout/generic/ScrollbarActivity.cpp
+++ b/layout/generic/ScrollbarActivity.cpp
@@ -6,7 +6,6 @@
 #include "ScrollbarActivity.h"
 #include "nsIScrollbarOwner.h"
 #include "nsIDOMEvent.h"
-#include "nsIDOMNSEvent.h"
 #include "nsIDOMElementCSSInlineStyle.h"
 #include "nsIDOMCSSStyleDeclaration.h"
 #include "nsIFrame.h"
diff --git a/layout/generic/TextOverflow.cpp b/layout/generic/TextOverflow.cpp
index 68ea7eda39db..30fd0448c01a 100644
--- a/layout/generic/TextOverflow.cpp
+++ b/layout/generic/TextOverflow.cpp
@@ -19,7 +19,6 @@
 #include "nsRect.h"
 #include "nsRenderingContext.h"
 #include "nsTextFrame.h"
-#include "nsStyleStructInlines.h"
 #include "mozilla/Util.h"
 #include "mozilla/Likely.h"
 
diff --git a/layout/generic/TextOverflow.h b/layout/generic/TextOverflow.h
index f9ecffc96d47..7c4e069a7343 100644
--- a/layout/generic/TextOverflow.h
+++ b/layout/generic/TextOverflow.h
@@ -8,14 +8,13 @@
 #define TextOverflow_h_
 
 #include "nsDisplayList.h"
-#include "nsLineBox.h"
-#include "nsStyleStruct.h"
 #include "nsTHashtable.h"
 #include "mozilla/Likely.h"
 #include <algorithm>
 
 class nsIScrollableFrame;
 class gfxTextRun;
+class nsLineBox;
 
 namespace mozilla {
 namespace css {
diff --git a/layout/generic/nsAbsoluteContainingBlock.cpp b/layout/generic/nsAbsoluteContainingBlock.cpp
index 8e52bc421fef..3a7fdf691870 100644
--- a/layout/generic/nsAbsoluteContainingBlock.cpp
+++ b/layout/generic/nsAbsoluteContainingBlock.cpp
@@ -13,12 +13,9 @@
 #include "nsContainerFrame.h"
 #include "nsGkAtoms.h"
 #include "nsIPresShell.h"
-#include "nsHTMLParts.h"
 #include "nsHTMLReflowState.h"
 #include "nsPresContext.h"
-#include "nsFrameManager.h"
 #include "nsCSSFrameConstructor.h"
-#include "nsIDocumentInlines.h"
 
 #ifdef DEBUG
 #include "nsBlockFrame.h"
diff --git a/layout/generic/nsBRFrame.cpp b/layout/generic/nsBRFrame.cpp
index 43acb9fa6c2b..91fc3b9c184c 100644
--- a/layout/generic/nsBRFrame.cpp
+++ b/layout/generic/nsBRFrame.cpp
@@ -7,7 +7,6 @@
 
 #include "nsCOMPtr.h"
 #include "nsFrame.h"
-#include "nsHTMLParts.h"
 #include "nsPresContext.h"
 #include "nsLineLayout.h"
 #include "nsStyleConsts.h"
@@ -17,7 +16,6 @@
 
 //FOR SELECTION
 #include "nsIContent.h"
-#include "nsFrameSelection.h"
 //END INCLUDES FOR SELECTION
 
 using namespace mozilla;
diff --git a/layout/generic/nsBlockFrame.cpp b/layout/generic/nsBlockFrame.cpp
index 7c9964c09345..d3790b48b813 100644
--- a/layout/generic/nsBlockFrame.cpp
+++ b/layout/generic/nsBlockFrame.cpp
@@ -10,7 +10,6 @@
  */
 
 #include "mozilla/DebugOnly.h"
-#include "mozilla/Likely.h"
 #include "mozilla/Util.h"
 
 #include "nsCOMPtr.h"
@@ -20,7 +19,6 @@
 #include "nsBlockReflowState.h"
 #include "nsBulletFrame.h"
 #include "nsLineBox.h"
-#include "nsInlineFrame.h"
 #include "nsLineLayout.h"
 #include "nsPlaceholderFrame.h"
 #include "nsStyleConsts.h"
@@ -28,23 +26,16 @@
 #include "nsPresContext.h"
 #include "nsIPresShell.h"
 #include "nsStyleContext.h"
-#include "nsView.h"
 #include "nsHTMLParts.h"
 #include "nsGkAtoms.h"
-#include "nsIDOMEvent.h"
 #include "nsGenericHTMLElement.h"
 #include "nsAttrValueInlines.h"
 #include "prprf.h"
-#include "nsStyleChangeList.h"
-#include "nsFrameSelection.h"
 #include "nsFloatManager.h"
-#include "nsIntervalSet.h"
 #include "prenv.h"
 #include "plstr.h"
-#include "nsGUIEvent.h"
 #include "nsError.h"
 #include "nsAutoPtr.h"
-#include "nsIServiceManager.h"
 #include "nsIScrollableFrame.h"
 #include <algorithm>
 #ifdef ACCESSIBILITY
@@ -54,18 +45,13 @@
 #include "nsDisplayList.h"
 #include "nsCSSAnonBoxes.h"
 #include "nsCSSFrameConstructor.h"
-#include "nsCSSRendering.h"
-#include "FrameLayerBuilder.h"
 #include "nsRenderingContext.h"
 #include "TextOverflow.h"
-#include "nsStyleStructInlines.h"
 
 #ifdef IBMBIDI
 #include "nsBidiPresUtils.h"
 #endif // IBMBIDI
 
-#include "nsIDOMHTMLHtmlElement.h"
-
 static const int MIN_LINES_NEEDING_CURSOR = 20;
 
 static const PRUnichar kDiscCharacter = 0x2022;
diff --git a/layout/generic/nsBlockFrame.h b/layout/generic/nsBlockFrame.h
index 21b4d3cec8a9..5254fd6967db 100644
--- a/layout/generic/nsBlockFrame.h
+++ b/layout/generic/nsBlockFrame.h
@@ -44,9 +44,7 @@ enum LineReflowStatus {
 class nsBlockReflowState;
 class nsBlockInFlowLineIterator;
 class nsBulletFrame;
-class nsLineBox;
 class nsFirstLineFrame;
-class nsIntervalSet;
 
 /**
  * Some invariants:
diff --git a/layout/generic/nsBlockReflowContext.cpp b/layout/generic/nsBlockReflowContext.cpp
index a73f1f0da0f3..08589a2c2125 100644
--- a/layout/generic/nsBlockReflowContext.cpp
+++ b/layout/generic/nsBlockReflowContext.cpp
@@ -7,17 +7,11 @@
 /* class that a parent frame uses to reflow a block frame */
 
 #include "nsBlockReflowContext.h"
-#include "nsLineLayout.h"
+#include "nsBlockReflowState.h"
 #include "nsFloatManager.h"
-#include "nsPresContext.h"
-#include "nsFrameManager.h"
-#include "nsIContent.h"
-#include "nsStyleContext.h"
 #include "nsContainerFrame.h"
 #include "nsBlockFrame.h"
 #include "nsLineBox.h"
-#include "nsGkAtoms.h"
-#include "nsCOMPtr.h"
 #include "nsLayoutUtils.h"
 
 #ifdef DEBUG
diff --git a/layout/generic/nsBlockReflowContext.h b/layout/generic/nsBlockReflowContext.h
index 8dcb7cc75649..a7fb8ff8a8b0 100644
--- a/layout/generic/nsBlockReflowContext.h
+++ b/layout/generic/nsBlockReflowContext.h
@@ -16,10 +16,8 @@ class nsBlockFrame;
 class nsBlockReflowState;
 struct nsHTMLReflowState;
 class nsLineBox;
-class nsIFrame;
 class nsPresContext;
 class nsLineLayout;
-struct nsStylePosition;
 struct nsBlockHorizontalAlign;
 
 /**
diff --git a/layout/generic/nsBlockReflowState.cpp b/layout/generic/nsBlockReflowState.cpp
index e483738cfc54..c572a3eb5f7d 100644
--- a/layout/generic/nsBlockReflowState.cpp
+++ b/layout/generic/nsBlockReflowState.cpp
@@ -6,21 +6,13 @@
 
 /* state used in reflow of block frames */
 
-#include "nsBlockReflowState.h"
-
 #include "mozilla/DebugOnly.h"
 
-#include "nsBlockReflowContext.h"
 #include "nsBlockFrame.h"
 #include "nsLineLayout.h"
 #include "nsPresContext.h"
-#include "nsGkAtoms.h"
 #include "nsIFrame.h"
-#include "nsFrameManager.h"
 #include "mozilla/AutoRestore.h"
-#include "FrameLayerBuilder.h"
-
-#include "nsINameSpaceManager.h"
 #include <algorithm>
 
 #ifdef DEBUG
diff --git a/layout/generic/nsBlockReflowState.h b/layout/generic/nsBlockReflowState.h
index 881586adcefd..6926d7b7a6cf 100644
--- a/layout/generic/nsBlockReflowState.h
+++ b/layout/generic/nsBlockReflowState.h
@@ -10,10 +10,10 @@
 
 #include "nsFloatManager.h"
 #include "nsLineBox.h"
-#include "nsFrameList.h"
 #include "nsHTMLReflowState.h"
 
 class nsBlockFrame;
+class nsFrameList;
 class nsOverflowContinuationTracker;
 
   // block reflow state flags
diff --git a/layout/generic/nsBulletFrame.cpp b/layout/generic/nsBulletFrame.cpp
index ffb6377cd309..ad75a1b68f08 100644
--- a/layout/generic/nsBulletFrame.cpp
+++ b/layout/generic/nsBulletFrame.cpp
@@ -8,27 +8,19 @@
 #include "nsCOMPtr.h"
 #include "nsBulletFrame.h"
 #include "nsGkAtoms.h"
-#include "nsHTMLParts.h"
-#include "nsContainerFrame.h"
 #include "nsGenericHTMLElement.h"
 #include "nsAttrValueInlines.h"
 #include "nsPresContext.h"
 #include "nsIPresShell.h"
 #include "nsIDocument.h"
 #include "nsRenderingContext.h"
-#include "nsILoadGroup.h"
-#include "nsIURL.h"
-#include "nsNetUtil.h"
 #include "prprf.h"
 #include "nsDisplayList.h"
 #include "nsCounterManager.h"
 
-#include "imgILoader.h"
 #include "imgIContainer.h"
 #include "imgRequestProxy.h"
 
-#include "nsIServiceManager.h"
-#include "nsIComponentManager.h"
 #include <algorithm>
 
 #ifdef ACCESSIBILITY
diff --git a/layout/generic/nsBulletFrame.h b/layout/generic/nsBulletFrame.h
index de8718e4eb33..70514bc07e22 100644
--- a/layout/generic/nsBulletFrame.h
+++ b/layout/generic/nsBulletFrame.h
@@ -10,9 +10,7 @@
 
 #include "mozilla/Attributes.h"
 #include "nsFrame.h"
-#include "nsStyleContext.h"
 
-#include "imgIRequest.h"
 #include "imgINotificationObserver.h"
 
 class imgIContainer;
diff --git a/layout/generic/nsCanvasFrame.cpp b/layout/generic/nsCanvasFrame.cpp
index 41555a46f023..89cf596c706b 100644
--- a/layout/generic/nsCanvasFrame.cpp
+++ b/layout/generic/nsCanvasFrame.cpp
@@ -6,26 +6,22 @@
 /* rendering object that goes directly inside the document's scrollbars */
 
 #include "nsCanvasFrame.h"
-#include "nsIServiceManager.h"
-#include "nsHTMLParts.h"
 #include "nsContainerFrame.h"
 #include "nsCSSRendering.h"
 #include "nsPresContext.h"
 #include "nsStyleContext.h"
 #include "nsRenderingContext.h"
-#include "nsGUIEvent.h"
-#include "nsStyleConsts.h"
 #include "nsGkAtoms.h"
-#include "nsEventStateManager.h"
 #include "nsIPresShell.h"
-#include "nsIScrollPositionListener.h"
 #include "nsDisplayList.h"
 #include "nsCSSFrameConstructor.h"
 #include "nsFrameManager.h"
 
 // for focus
 #include "nsIScrollableFrame.h"
+#ifdef DEBUG_CANVAS_FOCUS
 #include "nsIDocShell.h"
+#endif
 
 //#define DEBUG_CANVAS_FOCUS
 
diff --git a/layout/generic/nsCanvasFrame.h b/layout/generic/nsCanvasFrame.h
index dedf8899d2a8..57348480b00c 100644
--- a/layout/generic/nsCanvasFrame.h
+++ b/layout/generic/nsCanvasFrame.h
@@ -12,7 +12,6 @@
 #include "nsContainerFrame.h"
 #include "nsIScrollPositionListener.h"
 #include "nsDisplayList.h"
-#include "nsGkAtoms.h"
 
 class nsPresContext;
 class nsRenderingContext;
diff --git a/layout/generic/nsColumnSetFrame.cpp b/layout/generic/nsColumnSetFrame.cpp
index b81213924c15..a4422666460c 100644
--- a/layout/generic/nsColumnSetFrame.cpp
+++ b/layout/generic/nsColumnSetFrame.cpp
@@ -6,6 +6,8 @@
 /* rendering object for css3 multi-column layout */
 
 #include "nsColumnSetFrame.h"
+#include "nsCSSRendering.h"
+#include "nsDisplayList.h"
 
 using namespace mozilla;
 using namespace mozilla::layout;
diff --git a/layout/generic/nsColumnSetFrame.h b/layout/generic/nsColumnSetFrame.h
index e125fdca688d..31ad6cac64b1 100644
--- a/layout/generic/nsColumnSetFrame.h
+++ b/layout/generic/nsColumnSetFrame.h
@@ -7,19 +7,6 @@
 
 #include "mozilla/Attributes.h"
 #include "nsContainerFrame.h"
-#include "nsIContent.h"
-#include "nsIFrame.h"
-#include "nsISupports.h"
-#include "nsIAtom.h"
-#include "nsPresContext.h"
-#include "nsHTMLParts.h"
-#include "nsGkAtoms.h"
-#include "nsStyleConsts.h"
-#include "nsCOMPtr.h"
-#include "nsLayoutUtils.h"
-#include "nsDisplayList.h"
-#include "nsCSSRendering.h"
-#include <algorithm>
 
 class nsColumnSetFrame : public nsContainerFrame {
 public:
diff --git a/layout/generic/nsContainerFrame.cpp b/layout/generic/nsContainerFrame.cpp
index 8eba88728266..3903e7578a28 100644
--- a/layout/generic/nsContainerFrame.cpp
+++ b/layout/generic/nsContainerFrame.cpp
@@ -8,37 +8,26 @@
 #include "nsContainerFrame.h"
 
 #include "nsAbsoluteContainingBlock.h"
-#include "nsIContent.h"
 #include "nsIDocument.h"
 #include "nsPresContext.h"
 #include "nsStyleContext.h"
 #include "nsRect.h"
 #include "nsPoint.h"
-#include "nsGUIEvent.h"
 #include "nsStyleConsts.h"
 #include "nsView.h"
-#include "nsFrameManager.h"
 #include "nsIPresShell.h"
 #include "nsCOMPtr.h"
 #include "nsGkAtoms.h"
-#include "nsCSSAnonBoxes.h"
 #include "nsViewManager.h"
 #include "nsIWidget.h"
-#include "nsGfxCIID.h"
-#include "nsIServiceManager.h"
 #include "nsCSSRendering.h"
-#include "nsTransform2D.h"
-#include "nsRegion.h"
 #include "nsError.h"
 #include "nsDisplayList.h"
-#include "nsListControlFrame.h"
 #include "nsIBaseWindow.h"
-#include "nsThemeConstants.h"
 #include "nsBoxLayoutState.h"
-#include "nsRenderingContext.h"
 #include "nsCSSFrameConstructor.h"
+#include "nsBlockFrame.h"
 #include "mozilla/AutoRestore.h"
-#include "mozilla/dom/Element.h"
 #include <algorithm>
 
 #ifdef DEBUG
diff --git a/layout/generic/nsFirstLetterFrame.cpp b/layout/generic/nsFirstLetterFrame.cpp
index 3740eab87654..576152dc72fd 100644
--- a/layout/generic/nsFirstLetterFrame.cpp
+++ b/layout/generic/nsFirstLetterFrame.cpp
@@ -5,7 +5,6 @@
 
 /* rendering object for CSS :first-letter pseudo-element */
 
-#include "nsCOMPtr.h"
 #include "nsFirstLetterFrame.h"
 #include "nsPresContext.h"
 #include "nsStyleContext.h"
diff --git a/layout/generic/nsFlexContainerFrame.cpp b/layout/generic/nsFlexContainerFrame.cpp
index a40b92dd4e0b..c377f9bba6bf 100644
--- a/layout/generic/nsFlexContainerFrame.cpp
+++ b/layout/generic/nsFlexContainerFrame.cpp
@@ -993,7 +993,6 @@ private:
 
 // Utility class for managing our position along the cross axis along
 // the whole flex container (at a higher level than a single line)
-class SingleLineCrossAxisPositionTracker;
 class MOZ_STACK_CLASS CrossAxisPositionTracker : public PositionTracker {
 public:
   CrossAxisPositionTracker(nsFlexContainerFrame* aFlexContainerFrame,
diff --git a/layout/generic/nsFlexContainerFrame.h b/layout/generic/nsFlexContainerFrame.h
index 618187c878d0..2661b740bc1f 100644
--- a/layout/generic/nsFlexContainerFrame.h
+++ b/layout/generic/nsFlexContainerFrame.h
@@ -11,8 +11,6 @@
 #define nsFlexContainerFrame_h___
 
 #include "nsContainerFrame.h"
-#include "nsTArray.h"
-#include "mozilla/Types.h"
 
 nsIFrame* NS_NewFlexContainerFrame(nsIPresShell* aPresShell,
                                    nsStyleContext* aContext);
@@ -23,6 +21,7 @@ class FlexItem;
 class FlexboxAxisTracker;
 class MainAxisPositionTracker;
 class SingleLineCrossAxisPositionTracker;
+template <class T> class nsTArray;
 
 class nsFlexContainerFrame : public nsFlexContainerFrameSuper {
   NS_DECL_FRAMEARENA_HELPERS
diff --git a/layout/generic/nsFontInflationData.cpp b/layout/generic/nsFontInflationData.cpp
index 2675925586f8..89260ab52ac6 100644
--- a/layout/generic/nsFontInflationData.cpp
+++ b/layout/generic/nsFontInflationData.cpp
@@ -7,8 +7,6 @@
 
 #include "nsFontInflationData.h"
 #include "FramePropertyTable.h"
-#include "nsTextFragment.h"
-#include "nsIFormControlFrame.h"
 #include "nsTextControlFrame.h"
 #include "nsListControlFrame.h"
 #include "nsComboboxControlFrame.h"
diff --git a/layout/generic/nsFontInflationData.h b/layout/generic/nsFontInflationData.h
index b7378d93da92..59cb23619ae6 100644
--- a/layout/generic/nsFontInflationData.h
+++ b/layout/generic/nsFontInflationData.h
@@ -9,8 +9,6 @@
 #define nsFontInflationData_h_
 
 #include "nsIFrame.h"
-#include "nsLayoutUtils.h"
-#include "nsBlockFrame.h"
 
 struct nsHTMLReflowState;
 
diff --git a/layout/generic/nsFrame.cpp b/layout/generic/nsFrame.cpp
index 4b0c016d6795..6a9285d3929a 100644
--- a/layout/generic/nsFrame.cpp
+++ b/layout/generic/nsFrame.cpp
@@ -13,7 +13,6 @@
 #include "nsFrame.h"
 #include "nsFrameList.h"
 #include "nsPlaceholderFrame.h"
-#include "nsLineLayout.h"
 #include "nsIContent.h"
 #include "nsContentUtils.h"
 #include "nsIAtom.h"
@@ -25,9 +24,7 @@
 #include "nsViewManager.h"
 #include "nsIScrollableFrame.h"
 #include "nsPresContext.h"
-#include "nsCRT.h"
 #include "nsGUIEvent.h"
-#include "nsIDOMEvent.h"
 #include "nsAsyncDOMEvent.h"
 #include "nsStyleConsts.h"
 #include "nsIPresShell.h"
@@ -35,7 +32,6 @@
 #include "prprf.h"
 #include <stdarg.h>
 #include "nsFrameManager.h"
-#include "nsCSSRendering.h"
 #include "nsLayoutUtils.h"
 
 #include "nsIDOMNode.h"
@@ -43,17 +39,11 @@
 #include "nsISelection.h"
 #include "nsISelectionPrivate.h"
 #include "nsFrameSelection.h"
-#include "nsHTMLParts.h"
 #include "nsGkAtoms.h"
 #include "nsCSSAnonBoxes.h"
-#include "nsCSSPseudoElements.h"
-#include "nsCSSFrameConstructor.h"
 
 #include "nsFrameTraversal.h"
-#include "nsStyleChangeList.h"
-#include "nsIDOMRange.h"
 #include "nsRange.h"
-#include "nsITableCellLayout.h"//  "
 #include "nsITextControlFrame.h"
 #include "nsINameSpaceManager.h"
 #include "nsIPercentHeightObserver.h"
@@ -65,33 +55,25 @@
 #endif
 
 // For triple-click pref
-#include "nsIServiceManager.h"
 #include "imgIContainer.h"
 #include "imgIRequest.h"
-#include "nsLayoutCID.h"
-#include "nsUnicharUtils.h"
 #include "nsError.h"
 #include "nsContainerFrame.h"
 #include "nsBoxLayoutState.h"
 #include "nsBlockFrame.h"
 #include "nsDisplayList.h"
-#include "nsIObjectLoadingContent.h"
 #include "nsExpirationTracker.h"
 #include "nsSVGIntegrationUtils.h"
 #include "nsSVGEffects.h"
 #include "nsChangeHint.h"
 #include "nsDeckFrame.h"
-#include "nsTableFrame.h"
 #include "nsSubDocumentFrame.h"
 #include "nsSVGTextFrame2.h"
 
 #include "gfxContext.h"
 #include "nsRenderingContext.h"
-#include "CSSCalc.h"
 #include "nsAbsoluteContainingBlock.h"
 #include "nsFontInflationData.h"
-#include "nsAnimationManager.h"
-#include "nsTransitionManager.h"
 
 #include "mozilla/Preferences.h"
 #include "mozilla/LookAndFeel.h"
diff --git a/layout/generic/nsFrame.h b/layout/generic/nsFrame.h
index b466c5a0a22b..bca3b109ab73 100644
--- a/layout/generic/nsFrame.h
+++ b/layout/generic/nsFrame.h
@@ -12,14 +12,12 @@
 #include "mozilla/Likely.h"
 #include "nsBox.h"
 #include "nsRect.h"
-#include "nsString.h"
 #include "prlog.h"
 
 #include "nsIPresShell.h"
-#include "nsFrameSelection.h"
 #include "nsHTMLReflowState.h"
-#include "nsHTMLReflowMetrics.h"
 #include "nsHTMLParts.h"
+#include "nsISelectionDisplay.h"
 
 /**
  * nsFrame logging constants. We redefine the nspr
diff --git a/layout/generic/nsFrameList.cpp b/layout/generic/nsFrameList.cpp
index 7a63edec6b13..46a17cb1ada6 100644
--- a/layout/generic/nsFrameList.cpp
+++ b/layout/generic/nsFrameList.cpp
@@ -10,7 +10,6 @@
 #include "nsIPresShell.h"
 
 #ifdef IBMBIDI
-#include "nsCOMPtr.h"
 #include "nsGkAtoms.h"
 #include "nsILineIterator.h"
 #include "nsBidiPresUtils.h"
diff --git a/layout/generic/nsFrameList.h b/layout/generic/nsFrameList.h
index 006747cf566f..ec32f762914e 100644
--- a/layout/generic/nsFrameList.h
+++ b/layout/generic/nsFrameList.h
@@ -6,15 +6,13 @@
 #ifndef nsFrameList_h___
 #define nsFrameList_h___
 
-#include "nscore.h"
-#include "nsTraceRefcnt.h"
 #include <stdio.h> /* for FILE* */
 #include "nsDebug.h"
-#include "nsTArray.h"
 
 class nsIFrame;
 class nsIPresShell;
 class nsPresContext;
+template <class T> class nsTArray;
 
 namespace mozilla {
 namespace layout {
diff --git a/layout/generic/nsFrameSetFrame.cpp b/layout/generic/nsFrameSetFrame.cpp
index 0ff16fb649a1..03b97ee4f68d 100644
--- a/layout/generic/nsFrameSetFrame.cpp
+++ b/layout/generic/nsFrameSetFrame.cpp
@@ -8,7 +8,6 @@
 #include "mozilla/DebugOnly.h"
 #include "mozilla/Likely.h"
 
-#include "nsCOMPtr.h"
 #include "nsFrameSetFrame.h"
 #include "nsGenericHTMLElement.h"
 #include "nsAttrValueInlines.h"
@@ -16,22 +15,12 @@
 #include "nsContainerFrame.h"
 #include "nsPresContext.h"
 #include "nsIPresShell.h"
-#include "nsIComponentManager.h"
-#include "nsIStreamListener.h"
-#include "nsIURL.h"
-#include "nsIDocument.h"
-#include "nsINodeInfo.h"
-#include "nsView.h"
-#include "nsViewManager.h"
-#include "nsWidgetsCID.h"
 #include "nsGkAtoms.h"
-#include "nsStyleCoord.h"
 #include "nsStyleConsts.h"
 #include "nsStyleContext.h"
 #include "nsHTMLParts.h"
 #include "nsGUIEvent.h"
 #include "nsRenderingContext.h"
-#include "nsIServiceManager.h"
 #include "nsIDOMMutationEvent.h"
 #include "nsINameSpaceManager.h"
 #include "nsCSSAnonBoxes.h"
diff --git a/layout/generic/nsFrameSetFrame.h b/layout/generic/nsFrameSetFrame.h
index a9edde62fc38..fd693ba3e5f5 100644
--- a/layout/generic/nsFrameSetFrame.h
+++ b/layout/generic/nsFrameSetFrame.h
@@ -9,16 +9,11 @@
 #define nsHTMLFrameset_h___
 
 #include "mozilla/Attributes.h"
-#include "nsGkAtoms.h"
 #include "nsContainerFrame.h"
 #include "nsColor.h"
-#include "nsIObserver.h"
-#include "nsWeakPtr.h"
 
 class  nsIContent;
-class  nsIFrame;
 class  nsPresContext;
-class  nsRenderingContext;
 struct nsRect;
 struct nsHTMLReflowState;
 struct nsSize;
diff --git a/layout/generic/nsGfxScrollFrame.cpp b/layout/generic/nsGfxScrollFrame.cpp
index a3edadb91b39..acf5dd0ad252 100644
--- a/layout/generic/nsGfxScrollFrame.cpp
+++ b/layout/generic/nsGfxScrollFrame.cpp
@@ -7,12 +7,9 @@
 
 #include "base/compiler_specific.h"
 #include "nsCOMPtr.h"
-#include "nsHTMLParts.h"
 #include "nsPresContext.h"
-#include "nsIServiceManager.h"
 #include "nsView.h"
 #include "nsIScrollable.h"
-#include "nsViewManager.h"
 #include "nsContainerFrame.h"
 #include "nsGfxScrollFrame.h"
 #include "nsGkAtoms.h"
@@ -20,7 +17,6 @@
 #include "nsContentList.h"
 #include "nsIDocumentInlines.h"
 #include "nsFontMetrics.h"
-#include "nsIDocumentObserver.h"
 #include "nsBoxLayoutState.h"
 #include "nsINodeInfo.h"
 #include "nsScrollbarFrame.h"
@@ -28,24 +24,19 @@
 #include "nsITextControlFrame.h"
 #include "nsIDOMHTMLTextAreaElement.h"
 #include "nsNodeInfoManager.h"
-#include "nsIURI.h"
 #include "nsGUIEvent.h"
 #include "nsContentCreatorFunctions.h"
-#include "nsISupportsPrimitives.h"
 #include "nsAutoPtr.h"
 #include "nsPresState.h"
-#include "nsDocShellCID.h"
 #include "nsIHTMLDocument.h"
 #include "nsEventDispatcher.h"
 #include "nsContentUtils.h"
 #include "nsLayoutUtils.h"
 #include "nsBidiUtils.h"
-#include "nsFrameManager.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/LookAndFeel.h"
 #include "mozilla/dom/Element.h"
 #include <stdint.h>
-#include "mozilla/Util.h"
 #include "mozilla/MathAlgorithms.h"
 #include "FrameLayerBuilder.h"
 #include "nsSMILKeySpline.h"
@@ -54,8 +45,9 @@
 #include "mozilla/Attributes.h"
 #include "ScrollbarActivity.h"
 #include "nsRefreshDriver.h"
-#include "nsContentList.h"
 #include "nsThemeConstants.h"
+#include "nsSVGIntegrationUtils.h"
+#include "nsIScrollPositionListener.h"
 #include <algorithm>
 #include <cstdlib> // for std::abs(int/long)
 #include <cmath> // for std::abs(float/double)
diff --git a/layout/generic/nsGfxScrollFrame.h b/layout/generic/nsGfxScrollFrame.h
index a45271f7e0ce..b145d1a2f43f 100644
--- a/layout/generic/nsGfxScrollFrame.h
+++ b/layout/generic/nsGfxScrollFrame.h
@@ -12,25 +12,21 @@
 #include "nsContainerFrame.h"
 #include "nsIAnonymousContentCreator.h"
 #include "nsBoxFrame.h"
-#include "nsDisplayList.h"
 #include "nsIScrollableFrame.h"
-#include "nsIScrollPositionListener.h"
 #include "nsIStatefulFrame.h"
 #include "nsThreadUtils.h"
 #include "nsIReflowCallback.h"
 #include "nsBoxLayoutState.h"
 #include "nsQueryFrame.h"
-#include "nsCOMArray.h"
-#include "nsSVGIntegrationUtils.h"
 #include "nsExpirationTracker.h"
 
 class nsPresContext;
 class nsIPresShell;
 class nsIContent;
 class nsIAtom;
-class nsIDocument;
 class nsIScrollFrameInternal;
 class nsPresState;
+class nsIScrollPositionListener;
 struct ScrollReflowState;
 
 namespace mozilla {
diff --git a/layout/generic/nsHTMLCanvasFrame.cpp b/layout/generic/nsHTMLCanvasFrame.cpp
index bd3828a437f8..d75fe3ea69ca 100644
--- a/layout/generic/nsHTMLCanvasFrame.cpp
+++ b/layout/generic/nsHTMLCanvasFrame.cpp
@@ -5,20 +5,13 @@
 
 /* rendering object for the HTML <canvas> element */
 
-#include "nsHTMLParts.h"
-#include "nsCOMPtr.h"
-#include "nsIServiceManager.h"
 #include "nsGkAtoms.h"
-
 #include "nsHTMLCanvasFrame.h"
 #include "mozilla/dom/HTMLCanvasElement.h"
 #include "nsDisplayList.h"
 #include "nsLayoutUtils.h"
 #include "Layers.h"
 
-#include "nsTransform2D.h"
-
-#include "gfxContext.h"
 #include <algorithm>
 
 using namespace mozilla;
diff --git a/layout/generic/nsHTMLCanvasFrame.h b/layout/generic/nsHTMLCanvasFrame.h
index 363b6457d659..1601ba06775c 100644
--- a/layout/generic/nsHTMLCanvasFrame.h
+++ b/layout/generic/nsHTMLCanvasFrame.h
@@ -10,9 +10,6 @@
 
 #include "mozilla/Attributes.h"
 #include "nsContainerFrame.h"
-#include "nsString.h"
-#include "nsAString.h"
-#include "nsIIOService.h"
 #include "FrameLayerBuilder.h"
 
 namespace mozilla {
@@ -24,6 +21,7 @@ class LayerManager;
 
 class nsPresContext;
 class nsDisplayItem;
+class nsAString;
 
 nsIFrame* NS_NewHTMLCanvasFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 
diff --git a/layout/generic/nsHTMLReflowMetrics.h b/layout/generic/nsHTMLReflowMetrics.h
index a7f796f2ee37..e219fe06a3f4 100644
--- a/layout/generic/nsHTMLReflowMetrics.h
+++ b/layout/generic/nsHTMLReflowMetrics.h
@@ -8,9 +8,6 @@
 #ifndef nsHTMLReflowMetrics_h___
 #define nsHTMLReflowMetrics_h___
 
-#include <stdio.h>
-#include "nsISupports.h"
-#include "nsMargin.h"
 #include "nsRect.h"
 #include "nsBoundingMetrics.h"
 
diff --git a/layout/generic/nsHTMLReflowState.cpp b/layout/generic/nsHTMLReflowState.cpp
index 1c54e7b483cf..9ede7ffaae3e 100644
--- a/layout/generic/nsHTMLReflowState.cpp
+++ b/layout/generic/nsHTMLReflowState.cpp
@@ -5,7 +5,6 @@
 
 /* struct containing the input to nsIFrame::Reflow */
 
-#include "nsCOMPtr.h"
 #include "nsStyleConsts.h"
 #include "nsCSSAnonBoxes.h"
 #include "nsFrame.h"
@@ -20,11 +19,9 @@
 #include "nsImageFrame.h"
 #include "nsTableFrame.h"
 #include "nsTableCellFrame.h"
-#include "nsIServiceManager.h"
 #include "nsIPercentHeightObserver.h"
 #include "nsLayoutUtils.h"
 #include "mozilla/Preferences.h"
-#include "nsBidiUtils.h"
 #include "nsFontInflationData.h"
 #include <algorithm>
 
diff --git a/layout/generic/nsHTMLReflowState.h b/layout/generic/nsHTMLReflowState.h
index c793f6d904d1..4bb8bf1c4f5f 100644
--- a/layout/generic/nsHTMLReflowState.h
+++ b/layout/generic/nsHTMLReflowState.h
@@ -20,14 +20,6 @@ class nsRenderingContext;
 class nsFloatManager;
 class nsLineLayout;
 class nsIPercentHeightObserver;
-
-struct nsStyleDisplay;
-struct nsStyleVisibility;
-struct nsStylePosition;
-struct nsStyleBorder;
-struct nsStyleMargin;
-struct nsStylePadding;
-struct nsStyleText;
 struct nsHypotheticalBox;
 
 
diff --git a/layout/generic/nsImageFrame.cpp b/layout/generic/nsImageFrame.cpp
index aed7a1b163af..1ce8e609f544 100644
--- a/layout/generic/nsImageFrame.cpp
+++ b/layout/generic/nsImageFrame.cpp
@@ -7,7 +7,6 @@
 
 #include "mozilla/DebugOnly.h"
 
-#include "nsHTMLParts.h"
 #include "nsCOMPtr.h"
 #include "nsImageFrame.h"
 #include "nsIImageLoadingContent.h"
@@ -18,7 +17,6 @@
 #include "nsIPresShell.h"
 #include "nsGkAtoms.h"
 #include "nsIDocument.h"
-#include "nsINodeInfo.h"
 #include "nsContentUtils.h"
 #include "nsCSSAnonBoxes.h"
 #include "nsStyleContext.h"
@@ -26,22 +24,13 @@
 #include "nsStyleCoord.h"
 #include "nsTransform2D.h"
 #include "nsImageMap.h"
-#include "nsILinkHandler.h"
-#include "nsIURL.h"
 #include "nsIIOService.h"
 #include "nsILoadGroup.h"
 #include "nsISupportsPriority.h"
-#include "nsIServiceManager.h"
 #include "nsNetUtil.h"
-#include "nsContainerFrame.h"
-#include "prprf.h"
 #include "nsCSSRendering.h"
 #include "nsIDOMHTMLAnchorElement.h"
-#include "nsIDOMHTMLImageElement.h"
 #include "nsINameSpaceManager.h"
-#include "nsTextFragment.h"
-#include "nsIDOMHTMLMapElement.h"
-#include "nsIScriptSecurityManager.h"
 #include <algorithm>
 #ifdef ACCESSIBILITY
 #include "nsAccessibilityService.h"
@@ -58,8 +47,6 @@
 #include "nsCSSFrameConstructor.h"
 #include "nsIDOMRange.h"
 
-#include "nsIContentPolicy.h"
-#include "nsContentPolicyUtils.h"
 #include "nsEventStates.h"
 #include "nsError.h"
 #include "nsBidiUtils.h"
diff --git a/layout/generic/nsImageFrame.h b/layout/generic/nsImageFrame.h
index d982907da171..6900a0b8f536 100644
--- a/layout/generic/nsImageFrame.h
+++ b/layout/generic/nsImageFrame.h
@@ -18,19 +18,16 @@
 #include "imgIContainer.h"
 #include "mozilla/Attributes.h"
 
-class nsIFrame;
 class nsImageMap;
 class nsIURI;
 class nsILoadGroup;
 struct nsHTMLReflowState;
 struct nsHTMLReflowMetrics;
-struct nsSize;
 class nsDisplayImage;
 class nsPresContext;
 class nsImageFrame;
 class nsTransform2D;
 class nsImageLoadingContent;
-class imgRequestProxy;
 
 namespace mozilla {
 namespace layers {
diff --git a/layout/generic/nsImageMap.cpp b/layout/generic/nsImageMap.cpp
index 8cc50b8e7096..ad4499d4f434 100644
--- a/layout/generic/nsImageMap.cpp
+++ b/layout/generic/nsImageMap.cpp
@@ -12,18 +12,11 @@
 #include "nsReadableUtils.h"
 #include "nsRenderingContext.h"
 #include "nsPresContext.h"
-#include "nsIURL.h"
-#include "nsIServiceManager.h"
-#include "nsNetUtil.h"
-#include "nsTextFragment.h"
 #include "mozilla/dom/Element.h"
-#include "nsIDocument.h"
 #include "nsINameSpaceManager.h"
 #include "nsGkAtoms.h"
-#include "nsIPresShell.h"
 #include "nsImageFrame.h"
 #include "nsCoord.h"
-#include "nsIConsoleService.h"
 #include "nsIScriptError.h"
 #include "nsIStringBundle.h"
 #include "nsContentUtils.h"
diff --git a/layout/generic/nsImageMap.h b/layout/generic/nsImageMap.h
index 5d7f642eba7a..9fcbc40ae6aa 100644
--- a/layout/generic/nsImageMap.h
+++ b/layout/generic/nsImageMap.h
@@ -8,17 +8,18 @@
 #ifndef nsImageMap_h
 #define nsImageMap_h
 
-#include "nsISupports.h"
+#include "nsCOMPtr.h"
 #include "nsCoord.h"
 #include "nsTArray.h"
 #include "nsStubMutationObserver.h"
 #include "nsIDOMEventListener.h"
-#include "nsIFrame.h"
+#include "nsRect.h"
 
 class Area;
-class nsIDOMEvent;
 class nsRenderingContext;
 class nsImageFrame;
+class nsIFrame;
+class nsIContent;
 
 class nsImageMap : public nsStubMutationObserver,
                    public nsIDOMEventListener
diff --git a/layout/generic/nsInlineFrame.cpp b/layout/generic/nsInlineFrame.cpp
index 3368a01abfcd..ef40aba27374 100644
--- a/layout/generic/nsInlineFrame.cpp
+++ b/layout/generic/nsInlineFrame.cpp
@@ -6,14 +6,11 @@
 /* rendering object for CSS display:inline objects */
 
 #include "nsInlineFrame.h"
-#include "nsCOMPtr.h"
 #include "nsLineLayout.h"
 #include "nsBlockFrame.h"
 #include "nsPlaceholderFrame.h"
 #include "nsGkAtoms.h"
-#include "nsHTMLParts.h"
 #include "nsStyleContext.h"
-#include "nsIPresShell.h"
 #include "nsPresContext.h"
 #include "nsRenderingContext.h"
 #include "nsCSSAnonBoxes.h"
diff --git a/layout/generic/nsIntervalSet.cpp b/layout/generic/nsIntervalSet.cpp
index 92cd8c2989e9..cc72a811e692 100644
--- a/layout/generic/nsIntervalSet.cpp
+++ b/layout/generic/nsIntervalSet.cpp
@@ -7,7 +7,6 @@
 /* a set of ranges on a number-line */
 
 #include "nsIntervalSet.h"
-#include "nsAlgorithm.h"
 #include <new>
 #include <algorithm>
 
diff --git a/layout/generic/nsIntervalSet.h b/layout/generic/nsIntervalSet.h
index 5f4d02b7c054..9941df447373 100644
--- a/layout/generic/nsIntervalSet.h
+++ b/layout/generic/nsIntervalSet.h
@@ -10,7 +10,6 @@
 #define nsIntervalSet_h___
 
 #include "nsCoord.h"
-#include "nsDebug.h"
 
 typedef void *
 (* IntervalSetAlloc)(size_t aBytes, void *aClosure);
diff --git a/layout/generic/nsLeafFrame.cpp b/layout/generic/nsLeafFrame.cpp
index 52ca4484dca2..7802ae78aa7d 100644
--- a/layout/generic/nsLeafFrame.cpp
+++ b/layout/generic/nsLeafFrame.cpp
@@ -5,10 +5,7 @@
 
 /* base class for rendering objects that do not have child lists */
 
-#include "nsCOMPtr.h"
 #include "nsLeafFrame.h"
-#include "nsContainerFrame.h"
-#include "nsHTMLParts.h"
 #include "nsPresContext.h"
 
 nsLeafFrame::~nsLeafFrame()
diff --git a/layout/generic/nsLineBox.cpp b/layout/generic/nsLineBox.cpp
index 425f3574764f..cb484a724ee4 100644
--- a/layout/generic/nsLineBox.cpp
+++ b/layout/generic/nsLineBox.cpp
@@ -7,15 +7,12 @@
 /* representation of one line within a block frame, a CSS line box */
 
 #include "nsLineBox.h"
-#include "nsLineLayout.h"
 #include "prprf.h"
-#include "nsBlockFrame.h"
-#include "nsIFrame.h"
+#include "nsFrame.h"
 #include "nsPresArena.h"
 #ifdef IBMBIDI
 #include "nsBidiPresUtils.h"
 #endif
-#include "nsStyleStructInlines.h"
 #include "mozilla/Assertions.h"
 #include "mozilla/Likely.h"
 
diff --git a/layout/generic/nsLineLayout.cpp b/layout/generic/nsLineLayout.cpp
index 7b538bb91bb5..c1b089f9ec69 100644
--- a/layout/generic/nsLineLayout.cpp
+++ b/layout/generic/nsLineLayout.cpp
@@ -9,10 +9,8 @@
 #include "plarena.h"
 
 #include "mozilla/Util.h"
-#include "nsCOMPtr.h"
 #include "nsLineLayout.h"
 #include "nsBlockFrame.h"
-#include "nsInlineFrame.h"
 #include "nsStyleConsts.h"
 #include "nsContainerFrame.h"
 #include "nsFloatManager.h"
@@ -20,13 +18,9 @@
 #include "nsPresContext.h"
 #include "nsRenderingContext.h"
 #include "nsGkAtoms.h"
-#include "nsPlaceholderFrame.h"
 #include "nsIContent.h"
-#include "nsTextFragment.h"
-#include "nsBidiUtils.h"
 #include "nsLayoutUtils.h"
 #include "nsTextFrame.h"
-#include "nsCSSRendering.h"
 #include <algorithm>
 
 #ifdef DEBUG
diff --git a/layout/generic/nsLineLayout.h b/layout/generic/nsLineLayout.h
index d1ce47024889..ecb3e996558a 100644
--- a/layout/generic/nsLineLayout.h
+++ b/layout/generic/nsLineLayout.h
@@ -17,17 +17,12 @@
 #ifndef nsLineLayout_h___
 #define nsLineLayout_h___
 
-#include "nsFrame.h"
-#include "nsDeque.h"
 #include "nsLineBox.h"
 #include "nsBlockReflowState.h"
 #include "plarena.h"
 #include "gfxTypes.h"
 
-class nsBlockFrame;
-
 class nsFloatManager;
-class nsPlaceholderFrame;
 struct nsStyleText;
 
 class nsLineLayout {
diff --git a/layout/generic/nsObjectFrame.cpp b/layout/generic/nsObjectFrame.cpp
index 50d064ddfecd..76070019485a 100644
--- a/layout/generic/nsObjectFrame.cpp
+++ b/layout/generic/nsObjectFrame.cpp
@@ -6,7 +6,10 @@
 
 /* rendering objects for replaced elements implemented by a plugin */
 
+#ifdef XP_WIN
+// This is needed for DoublePassRenderingEvent.
 #include "mozilla/plugins/PluginMessageUtils.h"
+#endif
 
 #include "nscore.h"
 #include "nsCOMPtr.h"
@@ -15,89 +18,40 @@
 #include "nsWidgetsCID.h"
 #include "nsView.h"
 #include "nsViewManager.h"
-#include "nsIDOMEventListener.h"
-#include "nsIDOMDragEvent.h"
-#include "nsPluginHost.h"
 #include "nsString.h"
-#include "nsReadableUtils.h"
 #include "nsGkAtoms.h"
-#include "nsIAppShell.h"
-#include "nsIDocument.h"
-#include "nsINodeInfo.h"
-#include "nsIURL.h"
-#include "nsNetUtil.h"
 #include "nsIPluginInstanceOwner.h"
 #include "nsNPAPIPluginInstance.h"
-#include "nsIPluginTagInfo.h"
-#include "plstr.h"
-#include "nsILinkHandler.h"
-#include "nsIScrollPositionListener.h"
-#include "nsITimer.h"
-#include "nsIDocShellTreeItem.h"
-#include "nsIDocShellTreeOwner.h"
-#include "nsDocShellCID.h"
-#include "nsIWebBrowserChrome.h"
 #include "nsIDOMElement.h"
-#include "nsIDOMNodeList.h"
-#include "nsIDOMHTMLObjectElement.h"
-#include "nsIDOMHTMLEmbedElement.h"
-#include "nsIDOMHTMLAppletElement.h"
-#include "nsIDOMWindow.h"
-#include "nsIDocumentEncoder.h"
-#include "nsXPIDLString.h"
-#include "nsIDOMRange.h"
-#include "nsIPluginWidget.h"
 #include "nsGUIEvent.h"
 #include "nsRenderingContext.h"
 #include "npapi.h"
-#include "nsTransform2D.h"
-#include "nsIImageLoadingContent.h"
 #include "nsIObjectLoadingContent.h"
-#include "nsPIDOMWindow.h"
 #include "nsContentUtils.h"
 #include "nsDisplayList.h"
-#include "nsAttrName.h"
-#include "nsDataHashtable.h"
-#include "nsDOMClassInfo.h"
 #include "nsFocusManager.h"
 #include "nsLayoutUtils.h"
 #include "nsFrameManager.h"
-#include "nsComponentManagerUtils.h"
 #include "nsIObserverService.h"
-#include "nsIScrollableFrame.h"
-#include "mozilla/Preferences.h"
 #include "GeckoProfiler.h"
 #include <algorithm>
 
-// headers for plugin scriptability
-#include "nsIScriptGlobalObject.h"
-#include "nsIScriptContext.h"
-#include "nsIXPConnect.h"
-#include "nsIXPCScriptable.h"
-#include "nsIClassInfo.h"
-#include "nsIDOMClientRect.h"
-
 #include "nsObjectFrame.h"
 #include "nsIObjectFrame.h"
 #include "nsPluginNativeWindow.h"
-#include "nsIPluginDocument.h"
 #include "FrameLayerBuilder.h"
 
-#include "nsThreadUtils.h"
-
-#include "gfxContext.h"
-#include "gfxPlatform.h"
 #include "ImageLayers.h"
+#include "nsPluginInstanceOwner.h"
 
 #ifdef XP_WIN
 #include "gfxWindowsNativeDrawing.h"
 #include "gfxWindowsSurface.h"
 #endif
 
-#include "gfxImageSurface.h"
-#include "gfxUtils.h"
 #include "Layers.h"
 #include "ReadbackLayer.h"
+#include "ImageContainer.h"
 
 // accessibility support
 #ifdef ACCESSIBILITY
@@ -109,9 +63,6 @@
 #endif /* MOZ_LOGGING */
 #include "prlog.h"
 
-#include <errno.h>
-
-#include "nsContentCID.h"
 static NS_DEFINE_CID(kAppShellCID, NS_APPSHELL_CID);
 
 #ifdef XP_MACOSX
@@ -120,13 +71,6 @@ static NS_DEFINE_CID(kAppShellCID, NS_APPSHELL_CID);
 #include "mozilla/gfx/QuartzSupport.h"
 #endif
 
-#if defined(MOZ_WIDGET_GTK)
-#include <gdk/gdk.h>
-#include <gdk/gdkx.h>
-#include <gtk/gtk.h>
-#include "gfxXlibNativeRenderer.h"
-#endif
-
 #ifdef MOZ_X11
 #include "mozilla/X11Util.h"
 using mozilla::DefaultXDisplay;
diff --git a/layout/generic/nsObjectFrame.h b/layout/generic/nsObjectFrame.h
index e27240169e84..29d7066aa919 100644
--- a/layout/generic/nsObjectFrame.h
+++ b/layout/generic/nsObjectFrame.h
@@ -9,19 +9,22 @@
 #define nsObjectFrame_h___
 
 #include "mozilla/Attributes.h"
-#include "nsPluginInstanceOwner.h"
 #include "nsIObjectFrame.h"
 #include "nsFrame.h"
 #include "nsRegion.h"
 #include "nsDisplayList.h"
 #include "nsIReflowCallback.h"
 
-class nsPluginHost;
+#ifdef XP_WIN
+#include <windows.h> // For HWND :(
+#endif
+
 class nsPresContext;
 class nsRootPresContext;
 class nsDisplayPlugin;
 class nsIOSurface;
 class PluginBackgroundSink;
+class nsPluginInstanceOwner;
 
 namespace mozilla {
 namespace layers {
diff --git a/layout/generic/nsPageContentFrame.cpp b/layout/generic/nsPageContentFrame.cpp
index ff55ae5d1785..05095d6b89e2 100644
--- a/layout/generic/nsPageContentFrame.cpp
+++ b/layout/generic/nsPageContentFrame.cpp
@@ -3,18 +3,11 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "nsPageContentFrame.h"
-#include "nsPageFrame.h"
-#include "nsPlaceholderFrame.h"
 #include "nsCSSFrameConstructor.h"
-#include "nsContainerFrame.h"
-#include "nsHTMLParts.h"
-#include "nsIContent.h"
 #include "nsPresContext.h"
 #include "nsGkAtoms.h"
 #include "nsIPresShell.h"
-#include "nsReadableUtils.h"
 #include "nsSimplePageSequence.h"
-#include "nsDisplayList.h"
 
 nsIFrame*
 NS_NewPageContentFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
diff --git a/layout/generic/nsPageFrame.cpp b/layout/generic/nsPageFrame.cpp
index a8207b8a90a8..f712ca45ed60 100644
--- a/layout/generic/nsPageFrame.cpp
+++ b/layout/generic/nsPageFrame.cpp
@@ -5,23 +5,18 @@
 
 #include "nsPageFrame.h"
 #include "nsPresContext.h"
-#include "nsStyleContext.h"
 #include "nsRenderingContext.h"
 #include "nsGkAtoms.h"
 #include "nsIPresShell.h"
-#include "nsCSSFrameConstructor.h"
-#include "nsReadableUtils.h"
 #include "nsPageContentFrame.h"
 #include "nsDisplayList.h"
 #include "nsLayoutUtils.h" // for function BinarySearchForPosition
-#include "nsCSSRendering.h"
 #include "nsSimplePageSequence.h" // for nsSharedPageData
 #include "nsTextFormatter.h" // for page number localization formatting
 #ifdef IBMBIDI
 #include "nsBidiUtils.h"
 #endif
 #include "nsIPrintSettings.h"
-#include "nsRegion.h"
 
 #include "prlog.h"
 #ifdef PR_LOGGING 
diff --git a/layout/generic/nsSelection.cpp b/layout/generic/nsSelection.cpp
index d98acd169670..889f00d4f23e 100644
--- a/layout/generic/nsSelection.cpp
+++ b/layout/generic/nsSelection.cpp
@@ -13,23 +13,17 @@
 #include "mozilla/Attributes.h"
 
 #include "nsCOMPtr.h"
-#include "nsWeakReference.h"
-#include "nsIFactory.h"
 #include "nsString.h"
-#include "nsReadableUtils.h"
 #include "nsFrameSelection.h"
 #include "nsISelectionListener.h"
-#include "nsIComponentManager.h"
 #include "nsContentCID.h"
 #include "nsIContent.h"
-#include "nsIDOMElement.h"
 #include "nsIDOMNode.h"
 #include "nsRange.h"
 #include "nsCOMArray.h"
 #include "nsGUIEvent.h"
 #include "nsIDOMKeyEvent.h"
 #include "nsITableCellLayout.h"
-#include "nsIDOMNodeList.h"
 #include "nsTArray.h"
 #include "nsTableOuterFrame.h"
 #include "nsTableCellFrame.h"
@@ -41,8 +35,6 @@
 #include <algorithm>
 
 // for IBMBIDI
-#include "nsFrameTraversal.h"
-#include "nsILineIterator.h"
 #include "nsGkAtoms.h"
 #include "nsIFrameTraversal.h"
 #include "nsLayoutUtils.h"
@@ -65,7 +57,6 @@ static NS_DEFINE_CID(kFrameTraversalCID, NS_FRAMETRAVERSAL_CID);
 
 
 #include "nsITimer.h"
-#include "nsIServiceManager.h"
 #include "nsFrameManager.h"
 // notifications
 #include "nsIDOMDocument.h"
@@ -89,10 +80,6 @@ using namespace mozilla;
 
 static NS_DEFINE_IID(kCContentIteratorCID, NS_CONTENTITERATOR_CID);
 
-//PROTOTYPES
-class nsFrameSelection;
-class nsAutoScrollTimer;
-
 static bool IsValidSelectionPoint(nsFrameSelection *aFrameSel, nsINode *aNode);
 
 static nsIAtom *GetTag(nsINode *aNode);
diff --git a/layout/generic/nsSimplePageSequence.cpp b/layout/generic/nsSimplePageSequence.cpp
index 4cf3a11d6fce..a1723334f2d7 100644
--- a/layout/generic/nsSimplePageSequence.cpp
+++ b/layout/generic/nsSimplePageSequence.cpp
@@ -2,8 +2,7 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-#include "nsCOMPtr.h" 
-#include "nsReadableUtils.h"
+#include "nsCOMPtr.h"
 #include "nsSimplePageSequence.h"
 #include "nsPresContext.h"
 #include "gfxContext.h"
@@ -13,15 +12,15 @@
 #include "nsIPrintSettings.h"
 #include "nsPageFrame.h"
 #include "nsSubDocumentFrame.h"
-#include "nsStyleConsts.h"
 #include "nsRegion.h"
 #include "nsCSSFrameConstructor.h"
 #include "nsContentUtils.h"
 #include "nsDisplayList.h"
-#include "mozilla/Preferences.h"
 #include "nsHTMLCanvasFrame.h"
 #include "mozilla/dom/HTMLCanvasElement.h"
 #include "nsICanvasRenderingContextInternal.h"
+#include "nsIDateTimeFormat.h"
+#include "nsServiceManagerUtils.h"
 #include <algorithm>
 
 // DateTime Includes
@@ -31,8 +30,6 @@
 
 // Print Options
 #include "nsIPrintOptions.h"
-#include "nsGfxCIID.h"
-#include "nsIServiceManager.h"
 
 using namespace mozilla;
 using namespace mozilla::dom;
diff --git a/layout/generic/nsSimplePageSequence.h b/layout/generic/nsSimplePageSequence.h
index d17ff1d231d8..0333c48472d8 100644
--- a/layout/generic/nsSimplePageSequence.h
+++ b/layout/generic/nsSimplePageSequence.h
@@ -10,8 +10,16 @@
 #include "nsContainerFrame.h"
 #include "nsIPrintSettings.h"
 #include "nsIPrintOptions.h"
-#include "nsIDateTimeFormat.h"
-#include "mozilla/dom/HTMLCanvasElement.h"
+
+class nsIDateTimeFormat;
+
+namespace mozilla {
+namespace dom {
+
+class HTMLCanvasElement;
+
+}
+}
 
 //-----------------------------------------------
 // This class maintains all the data that 
diff --git a/layout/generic/nsSplittableFrame.cpp b/layout/generic/nsSplittableFrame.cpp
index d28e93bd244f..20b948014a57 100644
--- a/layout/generic/nsSplittableFrame.cpp
+++ b/layout/generic/nsSplittableFrame.cpp
@@ -9,9 +9,6 @@
  */
 
 #include "nsSplittableFrame.h"
-#include "nsIContent.h"
-#include "nsPresContext.h"
-#include "nsStyleContext.h"
 #include "nsContainerFrame.h"
 
 NS_IMPL_FRAMEARENA_HELPERS(nsSplittableFrame)
diff --git a/layout/generic/nsSubDocumentFrame.cpp b/layout/generic/nsSubDocumentFrame.cpp
index f547844299a0..bb2c36b17dc8 100644
--- a/layout/generic/nsSubDocumentFrame.cpp
+++ b/layout/generic/nsSubDocumentFrame.cpp
@@ -15,46 +15,25 @@
 #include "nsGenericHTMLElement.h"
 #include "nsAttrValueInlines.h"
 #include "nsIDocShell.h"
-#include "nsIDocShellLoadInfo.h"
-#include "nsIDocShellTreeItem.h"
-#include "nsIDocShellTreeNode.h"
-#include "nsIDocShellTreeOwner.h"
-#include "nsIBaseWindow.h"
 #include "nsIContentViewer.h"
 #include "nsPresContext.h"
 #include "nsIPresShell.h"
-#include "nsIComponentManager.h"
-#include "nsFrameManager.h"
-#include "nsIStreamListener.h"
-#include "nsIURL.h"
-#include "nsNetUtil.h"
 #include "nsIDocument.h"
 #include "nsView.h"
 #include "nsViewManager.h"
 #include "nsGkAtoms.h"
-#include "nsStyleCoord.h"
-#include "nsStyleContext.h"
 #include "nsStyleConsts.h"
 #include "nsFrameSetFrame.h"
 #include "nsIDOMHTMLFrameElement.h"
-#include "nsIDOMHTMLIFrameElement.h"
-#include "nsIDOMXULElement.h"
-#include "nsIScriptSecurityManager.h"
-#include "nsXPIDLString.h"
 #include "nsIScrollable.h"
 #include "nsINameSpaceManager.h"
-#include "nsWeakReference.h"
-#include "nsIDOMWindow.h"
 #include "nsDisplayList.h"
-#include "nsUnicharUtils.h"
 #include "nsIScrollableFrame.h"
 #include "nsIObjectLoadingContent.h"
 #include "nsLayoutUtils.h"
 #include "FrameLayerBuilder.h"
 #include "nsObjectFrame.h"
-#include "nsIServiceManager.h"
 #include "nsContentUtils.h"
-#include "LayerTreeInvalidation.h"
 #include "nsIPermissionManager.h"
 
 using namespace mozilla;
@@ -70,8 +49,6 @@ GetDocumentFromView(nsView* aView)
   return ps ? ps->GetDocument() : nullptr;
 }
 
-class AsyncFrameInit;
-
 nsSubDocumentFrame::nsSubDocumentFrame(nsStyleContext* aContext)
   : nsLeafFrame(aContext)
   , mIsInline(false)
diff --git a/layout/generic/nsTextFrame.cpp b/layout/generic/nsTextFrame.cpp
index 3a783ec3fed8..2d2a17004364 100644
--- a/layout/generic/nsTextFrame.cpp
+++ b/layout/generic/nsTextFrame.cpp
@@ -14,7 +14,6 @@
 
 #include "nsCOMPtr.h"
 #include "nsBlockFrame.h"
-#include "nsHTMLParts.h"
 #include "nsCRT.h"
 #include "nsSplittableFrame.h"
 #include "nsLineLayout.h"
@@ -30,9 +29,7 @@
 #include "nsCoord.h"
 #include "nsRenderingContext.h"
 #include "nsIPresShell.h"
-#include "nsITimer.h"
 #include "nsTArray.h"
-#include "nsIDocument.h"
 #include "nsCSSPseudoElements.h"
 #include "nsCSSFrameConstructor.h"
 #include "nsCompatibility.h"
@@ -43,17 +40,13 @@
 #include "nsPlaceholderFrame.h"
 #include "nsTextFrameUtils.h"
 #include "nsTextRunTransformations.h"
-#include "nsFrameManager.h"
 #include "nsTextFrameTextRunCache.h"
 #include "nsExpirationTracker.h"
 #include "nsUnicodeProperties.h"
-#include "nsUnicharUtilCIID.h"
 
 #include "nsTextFragment.h"
 #include "nsGkAtoms.h"
 #include "nsFrameSelection.h"
-#include "nsISelection.h"
-#include "nsIDOMRange.h"
 #include "nsRange.h"
 #include "nsCSSRendering.h"
 #include "nsContentUtils.h"
@@ -61,21 +54,16 @@
 #include "nsIWordBreaker.h"
 #include "nsGenericDOMDataNode.h"
 
-#include "nsILineIterator.h"
-
-#include "nsIServiceManager.h"
 #include <algorithm>
 #ifdef ACCESSIBILITY
 #include "nsAccessibilityService.h"
 #endif
 #include "nsAutoPtr.h"
 
-#include "nsBidiUtils.h"
 #include "nsPrintfCString.h"
 
 #include "gfxFont.h"
 #include "gfxContext.h"
-#include "gfxImageSurface.h"
 
 #include "mozilla/dom/Element.h"
 #include "mozilla/LookAndFeel.h"
diff --git a/layout/generic/nsTextFrame.h b/layout/generic/nsTextFrame.h
index 9837abf87e13..195402d0ed8b 100644
--- a/layout/generic/nsTextFrame.h
+++ b/layout/generic/nsTextFrame.h
@@ -12,7 +12,6 @@
 #include "nsLineBox.h"
 #include "gfxFont.h"
 #include "gfxSkipChars.h"
-#include "gfxContext.h"
 #include "nsDisplayList.h"
 
 class nsTextPaintStyle;
diff --git a/layout/generic/nsTextFrameUtils.cpp b/layout/generic/nsTextFrameUtils.cpp
index a6fff3cc4bd7..44fb1e70a86e 100644
--- a/layout/generic/nsTextFrameUtils.cpp
+++ b/layout/generic/nsTextFrameUtils.cpp
@@ -5,12 +5,11 @@
 
 #include "nsTextFrameUtils.h"
 
-#include "nsIWordBreaker.h"
-#include "gfxFont.h"
 #include "nsUnicharUtils.h"
 #include "nsBidiUtils.h"
 #include "nsIContent.h"
 #include "nsStyleStruct.h"
+#include "nsTextFragment.h"
 #include <algorithm>
 
 // XXX TODO implement transform of backslash to yen that nsTextTransform does
diff --git a/layout/generic/nsTextFrameUtils.h b/layout/generic/nsTextFrameUtils.h
index 451540af9a5a..b2be1f705d3a 100644
--- a/layout/generic/nsTextFrameUtils.h
+++ b/layout/generic/nsTextFrameUtils.h
@@ -6,9 +6,7 @@
 #ifndef NSTEXTFRAMEUTILS_H_
 #define NSTEXTFRAMEUTILS_H_
 
-#include "gfxFont.h"
 #include "gfxSkipChars.h"
-#include "nsTextFragment.h"
 
 class nsIContent;
 struct nsStyleText;
diff --git a/layout/generic/nsTextRunTransformations.cpp b/layout/generic/nsTextRunTransformations.cpp
index 1932ed51e55f..60f478ea6b01 100644
--- a/layout/generic/nsTextRunTransformations.cpp
+++ b/layout/generic/nsTextRunTransformations.cpp
@@ -7,13 +7,9 @@
 
 #include "mozilla/MemoryReporting.h"
 
-#include "nsTextFrameUtils.h"
-#include "gfxSkipChars.h"
 #include "nsGkAtoms.h"
-
 #include "nsStyleConsts.h"
 #include "nsStyleContext.h"
-#include "gfxContext.h"
 #include "nsUnicodeProperties.h"
 #include "nsSpecialCasingData.h"
 
diff --git a/layout/generic/nsVideoFrame.cpp b/layout/generic/nsVideoFrame.cpp
index c100642f26c2..defa6beca554 100644
--- a/layout/generic/nsVideoFrame.cpp
+++ b/layout/generic/nsVideoFrame.cpp
@@ -6,31 +6,23 @@
 
 /* rendering object for the HTML <video> element */
 
-#include "nsHTMLParts.h"
 #include "nsCOMPtr.h"
-#include "nsIServiceManager.h"
 #include "nsGkAtoms.h"
 
 #include "nsVideoFrame.h"
 #include "mozilla/dom/HTMLVideoElement.h"
 #include "nsIDOMHTMLVideoElement.h"
 #include "nsIDOMHTMLImageElement.h"
-#include "nsIDOMHTMLElement.h"
 #include "nsDisplayList.h"
 #include "nsGenericHTMLElement.h"
-#include "gfxContext.h"
-#include "gfxImageSurface.h"
 #include "nsPresContext.h"
-#include "nsTransform2D.h"
 #include "nsContentCreatorFunctions.h"
 #include "nsBoxLayoutState.h"
 #include "nsBoxFrame.h"
 #include "nsImageFrame.h"
 #include "nsIImageLoadingContent.h"
-#include "nsCSSRendering.h"
 #include "nsContentUtils.h"
 #include "nsCxPusher.h"
-#include "mozilla/layers/ShadowLayers.h"
 #include "ImageContainer.h"
 #include "ImageLayers.h"
 #include "nsContentList.h"
diff --git a/layout/generic/nsVideoFrame.h b/layout/generic/nsVideoFrame.h
index 4effdfeb3ad0..2a6fdd95010f 100644
--- a/layout/generic/nsVideoFrame.h
+++ b/layout/generic/nsVideoFrame.h
@@ -11,11 +11,6 @@
 
 #include "mozilla/Attributes.h"
 #include "nsContainerFrame.h"
-#include "nsString.h"
-#include "nsAString.h"
-#include "nsIIOService.h"
-#include "nsITimer.h"
-#include "nsTArray.h"
 #include "nsIAnonymousContentCreator.h"
 #include "FrameLayerBuilder.h"
 
@@ -26,8 +21,10 @@ class LayerManager;
 }
 }
 
+class nsAString;
 class nsPresContext;
 class nsDisplayItem;
+template <class T> class nsTArray;
 
 nsIFrame* NS_NewVideoFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 
diff --git a/layout/generic/nsViewportFrame.cpp b/layout/generic/nsViewportFrame.cpp
index 385809c124e9..c79f52db05dd 100644
--- a/layout/generic/nsViewportFrame.cpp
+++ b/layout/generic/nsViewportFrame.cpp
@@ -8,13 +8,9 @@
  * the document's scrollbars and contains fixed-positioned elements
  */
 
-#include "nsCOMPtr.h"
 #include "nsViewportFrame.h"
-#include "nsHTMLParts.h"
 #include "nsGkAtoms.h"
 #include "nsIScrollableFrame.h"
-#include "nsDisplayList.h"
-#include "FrameLayerBuilder.h"
 #include "nsSubDocumentFrame.h"
 #include "nsAbsoluteContainingBlock.h"
 #include "GeckoProfiler.h"
diff --git a/layout/generic/nsViewportFrame.h b/layout/generic/nsViewportFrame.h
index 6bdb97f0cbb1..7b129746faf8 100644
--- a/layout/generic/nsViewportFrame.h
+++ b/layout/generic/nsViewportFrame.h
@@ -13,7 +13,6 @@
 
 #include "mozilla/Attributes.h"
 #include "nsContainerFrame.h"
-#include "nsGkAtoms.h"
 
 class nsPresContext;
 
diff --git a/layout/mathml/nsMathMLmoFrame.cpp b/layout/mathml/nsMathMLmoFrame.cpp
index ca48373a6ab7..17cdbd6c55c2 100644
--- a/layout/mathml/nsMathMLmoFrame.cpp
+++ b/layout/mathml/nsMathMLmoFrame.cpp
@@ -10,6 +10,7 @@
 #include "nsStyleConsts.h"
 #include "nsRenderingContext.h"
 #include "nsContentUtils.h"
+#include "nsFrameSelection.h"
 
 #include "nsMathMLmoFrame.h"
 #include <algorithm>