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

webkit/renderer/compositor_bindings/web_scrollbar_layer_impl.cc

 // 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.
 
 #include "webkit/renderer/compositor_bindings/web_scrollbar_layer_impl.h"
 
+#include "cc/base/switches.h"
 #include "cc/layers/scrollbar_layer.h"
+#include "cc/layers/scrollbar_layer_interface.h"
+#include "cc/layers/solid_color_scrollbar_layer.h"
 #include "third_party/WebKit/public/platform/WebScrollbar.h"
 #include "webkit/renderer/compositor_bindings/scrollbar_impl.h"
 #include "webkit/renderer/compositor_bindings/web_layer_impl.h"
 
 using cc::ScrollbarLayer;
+using cc::SolidColorScrollbarLayer;
+
+namespace {
+
+cc::ScrollbarOrientation ConvertOrientation(
+    WebKit::WebScrollbar::Orientation orientation) {
+  return orientation == WebKit::WebScrollbar::Horizontal ? cc::HORIZONTAL
+                                                         : cc::VERTICAL;
+}
+
+const int kSolidColorScrollbarThumbThickness = 3;
+
+scoped_refptr<cc::Layer> CreateScrollbarLayer(
+    WebKit::WebScrollbar* scrollbar,
+    WebKit::WebScrollbarThemePainter painter,
+    WebKit::WebScrollbarThemeGeometry* geometry) {
+  if (cc::switches::AreOverlayScrollbarsEnabled()) {
+    return SolidColorScrollbarLayer::Create(
+        ConvertOrientation(scrollbar->orientation()),
+        kSolidColorScrollbarThumbThickness,
+        0);
+  } else {
+    return ScrollbarLayer::Create(
+        scoped_ptr<cc::Scrollbar>(new webkit::ScrollbarImpl(
+            make_scoped_ptr(scrollbar), painter, make_scoped_ptr(geometry))),
+        0);
+  }
+}
+
+}  // namespace
 
 namespace webkit {
 
 WebScrollbarLayerImpl::WebScrollbarLayerImpl(
     WebKit::WebScrollbar* scrollbar,
     WebKit::WebScrollbarThemePainter painter,
     WebKit::WebScrollbarThemeGeometry* geometry)
-    : layer_(new WebLayerImpl(ScrollbarLayer::Create(
-          scoped_ptr<cc::Scrollbar>(new ScrollbarImpl(
-              make_scoped_ptr(scrollbar),
-              painter,
-              make_scoped_ptr(geometry))).Pass(), 0))) {}
+    : layer_(new WebLayerImpl(
+          CreateScrollbarLayer(scrollbar, painter, geometry))) {}
 
 WebScrollbarLayerImpl::~WebScrollbarLayerImpl() {}
 
 WebKit::WebLayer* WebScrollbarLayerImpl::layer() { return layer_.get(); }
 
 void WebScrollbarLayerImpl::setScrollLayer(WebKit::WebLayer* layer) {
   int id = layer ? static_cast<WebLayerImpl*>(layer)->layer()->id() : 0;
-  static_cast<ScrollbarLayer*>(layer_->layer())->SetScrollLayerId(id);
+  layer_->layer()->ToScrollbarLayer()->SetScrollLayerId(id);
 }
 
 }  // namespace webkit