Let FrameView track object paint invalidations

third_party/WebKit/Source/core/frame/FrameView.h

Index: third_party/WebKit/Source/core/frame/FrameView.h
diff --git a/third_party/WebKit/Source/core/frame/FrameView.h b/third_party/WebKit/Source/core/frame/FrameView.h
index 467b20cc519eef9a22e0f2f2a6b0bbe397d0257f..252d84e8ed729c0bf15645afe62f79b80492eab5 100644
--- a/third_party/WebKit/Source/core/frame/FrameView.h
+++ b/third_party/WebKit/Source/core/frame/FrameView.h
@@ -63,6 +63,7 @@ class Cursor;
 class Element;
 class FloatSize;
 class HTMLFrameOwnerElement;
+class JSONArray;
 class LayoutPart;
 class LocalFrame;
 class KURL;
@@ -322,7 +323,10 @@ public:
     static void setInitialTracksPaintInvalidationsForTesting(bool);
 
     void setTracksPaintInvalidations(bool);
-    bool isTrackingPaintInvalidations() const { return m_isTrackingPaintInvalidations; }
+    bool isTrackingPaintInvalidations() const { return m_trackedObjectPaintInvalidations.get(); }
+
+    void trackObjectPaintInvalidation(const DisplayItemClient&, PaintInvalidationReason);
+    PassRefPtr<JSONArray> trackedObjectPaintInvalidationsAsJSON() const;
 
     using ScrollableAreaSet = HeapHashSet<Member<ScrollableArea>>;
     void addScrollableArea(ScrollableArea*);
@@ -819,8 +823,6 @@ private:
 
     bool m_safeToPropagateScrollToParent;
 
-    bool m_isTrackingPaintInvalidations; // Used for testing.
-
     unsigned m_visuallyNonEmptyCharacterCount;
     unsigned m_visuallyNonEmptyPixelCount;
     bool m_isVisuallyNonEmpty;
@@ -917,6 +919,12 @@ private:
 
     bool m_needsScrollbarsUpdate;
     bool m_suppressAdjustViewSize;
+
+    struct ObjectPaintInvalidation {
+        String name;
+        PaintInvalidationReason reason;
+    };
+    OwnPtr<Vector<ObjectPaintInvalidation>> m_trackedObjectPaintInvalidations;
 };
 
 inline void FrameView::incrementVisuallyNonEmptyCharacterCount(unsigned count)