When possible, draw the toolbar shadow with the compositor

chrome/browser/android/compositor/layer/toolbar_layer.h

 // Copyright 2014 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 CHROME_BROWSER_ANDROID_COMPOSITOR_LAYER_TOOLBAR_LAYER_H_
 #define CHROME_BROWSER_ANDROID_COMPOSITOR_LAYER_TOOLBAR_LAYER_H_
 
 #include <memory>
 
 #include "base/macros.h"
@@ skipping 13 matching lines @@
 
 class ToolbarLayer : public Layer {
  public:
   static scoped_refptr<ToolbarLayer> Create(
       ui::ResourceManager* resource_manager);
 
   // Implements Layer
   scoped_refptr<cc::Layer> layer() override;
 
   void PushResource(int toolbar_resource_id,
+                    int toolbar_shadow_resource_id,
                     int toolbar_background_color,
                     bool anonymize,
                     int  toolbar_textbox_background_color,
                     int url_bar_background_resource_id,
                     float url_bar_alpha,
                     bool show_debug,
-                    bool clip_shadow);
+                    bool needs_toolbar_shadow);
 
   void UpdateProgressBar(int progress_bar_x,
                          int progress_bar_y,
                          int progress_bar_width,
                          int progress_bar_height,
                          int progress_bar_color,
                          int progress_bar_background_x,
                          int progress_bar_background_y,
                          int progress_bar_background_width,
                          int progress_bar_background_height,
                          int progress_bar_background_color);
 
  protected:
   explicit ToolbarLayer(ui::ResourceManager* resource_manager);
   ~ToolbarLayer() override;
 
  private:
   ui::ResourceManager* resource_manager_;
 
   scoped_refptr<cc::Layer> layer_;
   scoped_refptr<cc::SolidColorLayer> toolbar_background_layer_;
+  scoped_refptr<cc::UIResourceLayer> toolbar_shadow_layer_;
   scoped_refptr<cc::NinePatchLayer> url_bar_background_layer_;
   scoped_refptr<cc::UIResourceLayer> bitmap_layer_;
   scoped_refptr<cc::SolidColorLayer> progress_bar_layer_;
   scoped_refptr<cc::SolidColorLayer> progress_bar_background_layer_;
   scoped_refptr<cc::SolidColorLayer> anonymize_layer_;
   scoped_refptr<cc::SolidColorLayer> debug_layer_;
 
   DISALLOW_COPY_AND_ASSIGN(ToolbarLayer);
 };
 
 }  //  namespace android
 }  //  namespace chrome
 
 #endif  // CHROME_BROWSER_ANDROID_COMPOSITOR_LAYER_TOOLBAR_LAYER_H_