Add more specific metrics for main thread scrolling reasons

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

 /*
    Copyright (C) 1997 Martin Jones (mjones@kde.org)
              (C) 1998 Waldo Bastian (bastian@kde.org)
              (C) 1998, 1999 Torben Weis (weis@kde.org)
              (C) 1999 Lars Knoll (knoll@kde.org)
              (C) 1999 Antti Koivisto (koivisto@kde.org)
    Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights
    reserved.
 
    This library is free software; you can redistribute it and/or
@@ skipping 787 matching lines @@
   // don't, both A and C should scroll on cc. Frame D should
   // scrolled on main thread as its ancestor B.
   void updateSubFrameScrollOnMainReason(const Frame&,
                                         MainThreadScrollingReasons);
   String mainThreadScrollingReasonsAsText() const;
   // Main thread scrolling reasons including reasons from ancestors.
   MainThreadScrollingReasons mainThreadScrollingReasons() const;
   // Main thread scrolling reasons for this object only. For all reasons,
   // see: mainThreadScrollingReasons().
   MainThreadScrollingReasons mainThreadScrollingReasonsPerFrame() const;
+  void adjustStyleRelatedMainThreadScrollingReasons(const uint32_t reason,
+                                                    bool increase);
+  MainThreadScrollingReasons getStyleRelatedMainThreadScrollingReasons() const;
+
   bool hasVisibleSlowRepaintViewportConstrainedObjects() const;
 
  protected:
   // Scroll the content via the compositor.
   bool scrollContentsFastPath(const IntSize& scrollDelta);
 
   // Scroll the content by invalidating everything.
   void scrollContentsSlowPath();
 
   ScrollBehavior scrollBehaviorStyle() const override;
@@ skipping 351 matching lines @@
   };
   std::unique_ptr<Vector<ObjectPaintInvalidation>>
       m_trackedObjectPaintInvalidations;
 
   // For Slimming Paint v2 only.
   std::unique_ptr<PaintController> m_paintController;
   std::unique_ptr<PaintArtifactCompositor> m_paintArtifactCompositor;
 
   bool m_isStoringCompositedLayerDebugInfo;
   MainThreadScrollingReasons m_mainThreadScrollingReasons;
+  // For recording main thread scrolling reasons
+  // due to layout object properties. e.g. opacity, transform.
+  // The size of the vector depends on the number of
+  // main thread scrolling reasons.
+  Vector<int> m_mainThreadScrollingReasonsCounter;
 };
 
 inline void FrameView::incrementVisuallyNonEmptyCharacterCount(unsigned count) {
   if (m_isVisuallyNonEmpty)
     return;
   m_visuallyNonEmptyCharacterCount += count;
   // Use a threshold value to prevent very small amounts of visible content from
   // triggering didMeaningfulLayout.  The first few hundred characters rarely
   // contain the interesting content of the page.
   static const unsigned visualCharacterThreshold = 200;
@@ skipping 20 matching lines @@
                   widget.isFrameView());
 DEFINE_TYPE_CASTS(FrameView,
                   ScrollableArea,
                   scrollableArea,
                   scrollableArea->isFrameView(),
                   scrollableArea.isFrameView());
 
 }  // namespace blink
 
 #endif  // FrameView_h