When possible, draw the toolbar shadow with the compositor

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

 // 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.
 
 #include "chrome/browser/android/compositor/layer/toolbar_layer.h"
 
 #include "cc/layers/nine_patch_layer.h"
 #include "cc/layers/solid_color_layer.h"
 #include "cc/layers/ui_resource_layer.h"
 #include "cc/resources/scoped_ui_resource.h"
 #include "content/public/browser/android/compositor.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/android/resources/resource_manager.h"
 
 namespace chrome {
 namespace android {
 
 // static
 scoped_refptr<ToolbarLayer> ToolbarLayer::Create(
     ui::ResourceManager* resource_manager) {
   return make_scoped_refptr(new ToolbarLayer(resource_manager));
 }
 
 scoped_refptr<cc::Layer> ToolbarLayer::layer() {
   return layer_;
 }
 
 void ToolbarLayer::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 show_shadow) {
   ui::ResourceManager::Resource* resource =
       resource_manager_->GetResource(ui::ANDROID_RESOURCE_TYPE_DYNAMIC,
                                      toolbar_resource_id);
+  ui::ResourceManager::Resource* shadow_resource =
+      resource_manager_->GetResource(ui::ANDROID_RESOURCE_TYPE_STATIC,
+                                     toolbar_shadow_resource_id);
 
   // Ensure the toolbar resource is available before making the layer visible.
   layer_->SetHideLayerAndSubtree(!resource);
   if (!resource)
     return;
 
   // This layer effectively draws over the space it takes for shadows.  Set the
   // bounds to the non-shadow size so that other things can properly line up.
   // Padding height does not include the height of the tabstrip, so we add
   // it explicitly by adding y offset.
@@ skipping 30 matching lines @@
     url_bar_background_layer_->SetAperture(
         url_bar_background_resource->aperture);
     url_bar_background_layer_->SetBounds(url_bar_size);
     url_bar_background_layer_->SetPosition(url_bar_position);
     url_bar_background_layer_->SetOpacity(url_bar_alpha);
   }
 
   bitmap_layer_->SetUIResourceId(resource->ui_resource->id());
   bitmap_layer_->SetBounds(resource->size);
 
-  layer_->SetMasksToBounds(clip_shadow);
+  if (shadow_resource) {
+    toolbar_shadow_layer_->SetUIResourceId(shadow_resource->ui_resource->id());
+    toolbar_shadow_layer_->SetBounds(
+        gfx::Size(resource->size.width(), shadow_resource->size.height()));
+    toolbar_shadow_layer_->SetPosition(
+        gfx::PointF(0.0f, resource->padding.size().height()));
+    toolbar_shadow_layer_->SetHideLayerAndSubtree(!show_shadow);
+  }
 
   anonymize_layer_->SetHideLayerAndSubtree(!anonymize);
   if (anonymize) {
     anonymize_layer_->SetPosition(gfx::PointF(resource->aperture.origin()));
     anonymize_layer_->SetBounds(resource->aperture.size());
     anonymize_layer_->SetBackgroundColor(toolbar_textbox_background_color);
   }
 
   debug_layer_->SetBounds(resource->size);
   if (show_debug && !debug_layer_->parent())
@@ skipping 34 matching lines @@
     progress_bar_layer_->SetBounds(
         gfx::Size(progress_bar_width, progress_bar_height));
     progress_bar_layer_->SetBackgroundColor(progress_bar_color);
   }
 }
 
 ToolbarLayer::ToolbarLayer(ui::ResourceManager* resource_manager)
     : resource_manager_(resource_manager),
       layer_(cc::Layer::Create()),
       toolbar_background_layer_(cc::SolidColorLayer::Create()),
+      toolbar_shadow_layer_(cc::UIResourceLayer::Create()),
       url_bar_background_layer_(cc::NinePatchLayer::Create()),
       bitmap_layer_(cc::UIResourceLayer::Create()),
       progress_bar_layer_(cc::SolidColorLayer::Create()),
       progress_bar_background_layer_(cc::SolidColorLayer::Create()),
       anonymize_layer_(cc::SolidColorLayer::Create()),
       debug_layer_(cc::SolidColorLayer::Create()) {
   toolbar_background_layer_->SetIsDrawable(true);
   layer_->AddChild(toolbar_background_layer_);
 
+  toolbar_shadow_layer_->SetIsDrawable(true);
+  layer_->AddChild(toolbar_shadow_layer_);
+
   url_bar_background_layer_->SetIsDrawable(true);
   url_bar_background_layer_->SetFillCenter(true);
   layer_->AddChild(url_bar_background_layer_);
 
   bitmap_layer_->SetIsDrawable(true);
   layer_->AddChild(bitmap_layer_);
 
   progress_bar_background_layer_->SetIsDrawable(true);
   progress_bar_background_layer_->SetHideLayerAndSubtree(true);
   layer_->AddChild(progress_bar_background_layer_);
 
   progress_bar_layer_->SetIsDrawable(true);
   progress_bar_layer_->SetHideLayerAndSubtree(true);
   layer_->AddChild(progress_bar_layer_);
 
   anonymize_layer_->SetIsDrawable(true);
   anonymize_layer_->SetBackgroundColor(SK_ColorWHITE);
   layer_->AddChild(anonymize_layer_);
 
   debug_layer_->SetIsDrawable(true);
   debug_layer_->SetBackgroundColor(SK_ColorGREEN);
   debug_layer_->SetOpacity(0.5f);
 }
 
 ToolbarLayer::~ToolbarLayer() {
 }
 
 }  //  namespace android
 }  //  namespace chrome