Refactor cc scrollbar layers to separate solid-color vs desktop.

webkit/renderer/compositor_bindings/web_compositor_support_impl.cc

Index: webkit/renderer/compositor_bindings/web_compositor_support_impl.cc
diff --git a/webkit/renderer/compositor_bindings/web_compositor_support_impl.cc b/webkit/renderer/compositor_bindings/web_compositor_support_impl.cc
index 4cb5dd93425d6e2ddccdd8476f640233b126c12b..b1dd837fa7797c352fb4b9cfd13505a633625092 100644
--- a/webkit/renderer/compositor_bindings/web_compositor_support_impl.cc
+++ b/webkit/renderer/compositor_bindings/web_compositor_support_impl.cc
@@ -78,7 +78,20 @@ WebScrollbarLayer* WebCompositorSupportImpl::createScrollbarLayer(
     WebScrollbar* scrollbar,
     WebScrollbarThemePainter painter,
     WebScrollbarThemeGeometry* geometry) {
+// TODO(wjmaclean) Remove the Android-specific if-clause here once the
+// Blink-side changes are made to call createSolidColorScrollbarLayer()
+// directly.
+#if defined(OS_ANDROID)
+  const int kThumbThickness = 3;
+  return new WebScrollbarLayerImpl(scrollbar->orientation(), kThumbThickness);
+#else
   return new WebScrollbarLayerImpl(scrollbar, painter, geometry);
+#endif
+}
+
+WebScrollbarLayer* WebCompositorSupportImpl::createSolidColorScrollbarLayer(
+      WebKit::WebScrollbar::Orientation orientation, int thumb_thickness) {
+  return new WebScrollbarLayerImpl(orientation, thumb_thickness);
 }
 
 WebAnimation* WebCompositorSupportImpl::createAnimation(