Add support for setting TrackStart on solid color layers.

webkit/renderer/compositor_bindings/web_scrollbar_layer_impl.h

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef WEBKIT_RENDERER_COMPOSITOR_BINDINGS_WEB_SCROLLBAR_LAYER_IMPL_H_
 #define WEBKIT_RENDERER_COMPOSITOR_BINDINGS_WEB_SCROLLBAR_LAYER_IMPL_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "third_party/WebKit/public/platform/WebScrollbar.h"
 #include "third_party/WebKit/public/platform/WebScrollbarLayer.h"
@@ skipping 10 matching lines @@
 
 class WebScrollbarLayerImpl : public blink::WebScrollbarLayer {
  public:
   WEBKIT_COMPOSITOR_BINDINGS_EXPORT WebScrollbarLayerImpl(
       blink::WebScrollbar* scrollbar,
       blink::WebScrollbarThemePainter painter,
       blink::WebScrollbarThemeGeometry* geometry);
   WEBKIT_COMPOSITOR_BINDINGS_EXPORT WebScrollbarLayerImpl(
       blink::WebScrollbar::Orientation orientation,
       int thumb_thickness,
+      int track_start,
       bool is_left_side_vertical_scrollbar);
   virtual ~WebScrollbarLayerImpl();
 
   // blink::WebScrollbarLayer implementation.
   virtual blink::WebLayer* layer();
   virtual void setScrollLayer(blink::WebLayer* layer);
   virtual void setClipLayer(blink::WebLayer* layer);
 
  private:
   scoped_ptr<WebLayerImpl> layer_;
 
   DISALLOW_COPY_AND_ASSIGN(WebScrollbarLayerImpl);
 };
 
 }  // namespace webkit
 
 #endif  // WEBKIT_RENDERER_COMPOSITOR_BINDINGS_WEB_SCROLLBAR_LAYER_IMPL_H_