Move paint invalidation after compositing update

Source/core/frame/FrameView.h

Index: Source/core/frame/FrameView.h
diff --git a/Source/core/frame/FrameView.h b/Source/core/frame/FrameView.h
index 4d04b781ab55040c9b9ac19c029117eb277799c0..be9b4e8391ef0b1a6ced64868239b56c57e7d4f4 100644
--- a/Source/core/frame/FrameView.h
+++ b/Source/core/frame/FrameView.h
@@ -96,8 +96,8 @@ public:
     bool canInvalidatePaintDuringPerformLayout() const { return m_canInvalidatePaintDuringPerformLayout; }
 
     RenderObject* layoutRoot(bool onlyDuringLayout = false) const;
-    void clearLayoutSubtreeRoot() { m_layoutSubtreeRoot = 0; }
     int layoutCount() const { return m_layoutCount; }
+    void rendererWillBeDestroyed(RenderObject*);
 
     bool needsLayout() const;
     void setNeedsLayout();
@@ -219,6 +219,8 @@ public:
     void updateLayoutAndStyleForPainting();
     void updateLayoutAndStyleIfNeededRecursive();
 
+    void invalidateTreeIfNeededRecursive();
+
     void incrementVisuallyNonEmptyCharacterCount(unsigned);
     void incrementVisuallyNonEmptyPixelCount(const IntSize&);
     void setIsVisuallyNonEmpty() { m_isVisuallyNonEmpty = true; }
@@ -361,7 +363,7 @@ private:
     void scheduleOrPerformPostLayoutTasks();
     void performPostLayoutTasks();
 
-    void invalidateTree(RenderObject* root);
+    void invalidateTreeIfNeeded();
 
     void gatherDebugLayoutRects(RenderObject* layoutRoot);
 
@@ -436,6 +438,13 @@ private:
     bool m_hasPendingLayout;
     RenderObject* m_layoutSubtreeRoot;
 
+    // These are copies of the layout roots so that we can
+    // generate invalidations in their own phase. While the
+    // HashSet could potentially yield to unbounded memory,
+    // most layouts share a limited number of layout roots
+    // (6 at most in LayoutTests/fast/).
+    HashSet<RenderObject*> m_paintInvalidationSubtreeRoots;
+
     bool m_layoutSchedulingEnabled;
     bool m_inPerformLayout;
     bool m_canInvalidatePaintDuringPerformLayout;