Add a UseCounter for CustomScrollbar

Source/core/rendering/RenderScrollbarPart.cpp

 /*
  * Copyright (C) 2008 Apple Inc. All Rights Reserved.
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  * modification, are permitted provided that the following conditions
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  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
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 #include "config.h"
 #include "core/rendering/RenderScrollbarPart.h"
 
+#include "core/frame/UseCounter.h"
 #include "core/rendering/PaintInfo.h"
 #include "core/rendering/RenderScrollbar.h"
 #include "core/rendering/RenderScrollbarTheme.h"
 #include "core/rendering/RenderView.h"
 #include "platform/LengthFunctions.h"
 
 namespace blink {
 
 RenderScrollbarPart::RenderScrollbarPart(RenderScrollbar* scrollbar, ScrollbarPart part)
     : RenderBlock(0)
     , m_scrollbar(scrollbar)
     , m_part(part)
 {
 }
 
 RenderScrollbarPart::~RenderScrollbarPart()
 {
 }
 
+static void recordScrollbarPartStats(Document* document, ScrollbarPart part)

[esprehn, 2014/10/31 17:21:22]

This should take the document reference instead of all the *document below.

+{
+    switch (part) {
+    case BackButtonStartPart:
+    case ForwardButtonStartPart:
+    case BackButtonEndPart:
+    case ForwardButtonEndPart:
+        UseCounter::count(*document, UseCounter::CSSSelectorPseudoScrollbarButton);
+        break;
+    case BackTrackPart:
+    case ForwardTrackPart:
+        UseCounter::count(*document, UseCounter::CSSSelectorPseudoScrollbarTrackPiece);
+        break;
+    case ThumbPart:
+        UseCounter::count(*document, UseCounter::CSSSelectorPseudoScrollbarThumb);
+        break;
+    case TrackBGPart:
+        UseCounter::count(*document, UseCounter::CSSSelectorPseudoScrollbarTrack);
+        break;
+    case ScrollbarBGPart:
+        UseCounter::count(*document, UseCounter::CSSSelectorPseudoScrollbar);
+        break;
+    case NoPart:
+    case AllParts:
+        break;
+    }
+}
+
 RenderScrollbarPart* RenderScrollbarPart::createAnonymous(Document* document, RenderScrollbar* scrollbar, ScrollbarPart part)
 {
     RenderScrollbarPart* renderer = new RenderScrollbarPart(scrollbar, part);
+    recordScrollbarPartStats(document, part);
     renderer->setDocumentForAnonymous(document);
     return renderer;
 }
 
 void RenderScrollbarPart::layout()
 {
     setLocation(LayoutPoint()); // We don't worry about positioning ourselves. We're just determining our minimum width/height.
     if (m_scrollbar->orientation() == HorizontalScrollbar)
         layoutHorizontalPart();
     else
@@ skipping 109 matching lines @@
 }
 
 RenderObject* RenderScrollbarPart::rendererOwningScrollbar() const
 {
     if (!m_scrollbar)
         return 0;
     return m_scrollbar->owningRenderer();
 }
 
 }