Subtree caching implementation in blink-core

Source/core/layout/LayoutPart.cpp

Index: Source/core/layout/LayoutPart.cpp
diff --git a/Source/core/layout/LayoutPart.cpp b/Source/core/layout/LayoutPart.cpp
index 3bd9e7fbba2e5aafaf2d74491450b2ac38532fee..34254ef8b4d8b432bcc19bbdf02a862da075ec37 100644
--- a/Source/core/layout/LayoutPart.cpp
+++ b/Source/core/layout/LayoutPart.cpp
@@ -336,10 +336,18 @@ void LayoutPart::invalidatePaintOfSubtreesIfNeeded(PaintInvalidationState& paint
     if (widget() && widget()->isFrameView()) {
         FrameView* childFrameView = toFrameView(widget());
         PaintInvalidationState childViewPaintInvalidationState(*childFrameView->layoutView(), paintInvalidationState);
-        toFrameView(widget())->invalidateTreeIfNeeded(childViewPaintInvalidationState);
+        childFrameView->invalidateTreeIfNeeded(childViewPaintInvalidationState);
     }
 
     LayoutReplaced::invalidatePaintOfSubtreesIfNeeded(paintInvalidationState);
 }
 
+bool LayoutPart::clearRepaintFlagsOfSubtrees()
+{
+    bool result = LayoutReplaced::clearRepaintFlagsOfSubtrees();
+    if (widget() && widget()->isFrameView())
+        result &= toFrameView(widget())->layoutView()->clearRepaintFlagsRecursively();
+    return result;
+}
+
 }