Introduce separate client and init path for single-threaded cc

content/renderer/gpu/render_widget_compositor.cc

 // Copyright (c) 2013 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 "content/renderer/gpu/render_widget_compositor.h"
 
 #include <limits>
 #include <string>
 
 #if defined(OS_ANDROID)
@@ skipping 289 matching lines @@
 #elif !defined(OS_MACOSX)
   if (cmd->HasSwitch(switches::kEnableOverlayScrollbars)) {
     settings.scrollbar_animator = cc::LayerTreeSettings::Thinning;
   }
   if (cmd->HasSwitch(cc::switches::kEnablePinchVirtualViewport) ||
       cmd->HasSwitch(switches::kEnableOverlayScrollbars)) {
     settings.solid_color_scrollbar_color = SkColorSetARGB(128, 128, 128, 128);
   }
 #endif
 
-  if (!compositor->initialize(settings))
+  if (!compositor->Initialize(settings))
     return scoped_ptr<RenderWidgetCompositor>();
 
   return compositor.Pass();
 }
 
 RenderWidgetCompositor::RenderWidgetCompositor(RenderWidget* widget,
                                                bool threaded)
     : threaded_(threaded),
       suppress_schedule_composite_(false),
       widget_(widget) {
@@ skipping 85 matching lines @@
   return layer_tree_host_->root_layer();
 }
 
 bool RenderWidgetCompositor::ScheduleMicroBenchmark(
     const std::string& name,
     scoped_ptr<base::Value> value,
     const base::Callback<void(scoped_ptr<base::Value>)>& callback) {
   return layer_tree_host_->ScheduleMicroBenchmark(name, value.Pass(), callback);
 }
 
-bool RenderWidgetCompositor::initialize(cc::LayerTreeSettings settings) {
+bool RenderWidgetCompositor::Initialize(cc::LayerTreeSettings settings) {
   scoped_refptr<base::MessageLoopProxy> compositor_message_loop_proxy =
       RenderThreadImpl::current()->compositor_message_loop_proxy();
-  layer_tree_host_ = cc::LayerTreeHost::Create(
-      this, NULL, settings, compositor_message_loop_proxy);
+  if (compositor_message_loop_proxy.get()) {
+    layer_tree_host_ = cc::LayerTreeHost::CreateThreaded(
+        this, NULL, settings, compositor_message_loop_proxy);
+  } else {
+    layer_tree_host_ = cc::LayerTreeHost::CreateSingleThreaded(
+        this, this, NULL, settings);
+  }
   return layer_tree_host_;
 }
 
 void RenderWidgetCompositor::setSurfaceReady() {
   layer_tree_host_->SetLayerTreeHostClientReady();
 }
 
 void RenderWidgetCompositor::setRootLayer(const WebKit::WebLayer& layer) {
   layer_tree_host_->SetRootLayer(
       static_cast<const webkit::WebLayerImpl*>(&layer)->layer());
@@ skipping 200 matching lines @@
 }
 
 void RenderWidgetCompositor::DidCommitAndDrawFrame() {
   widget_->didCommitAndDrawCompositorFrame();
 }
 
 void RenderWidgetCompositor::DidCompleteSwapBuffers() {
   widget_->didCompleteSwapBuffers();
 }
 
+scoped_refptr<cc::ContextProvider>
+RenderWidgetCompositor::OffscreenContextProvider() {
+  return RenderThreadImpl::current()->OffscreenCompositorContextProvider();
+}
+
 void RenderWidgetCompositor::ScheduleComposite() {
   if (!suppress_schedule_composite_)
     widget_->scheduleComposite();
 }
 
-scoped_refptr<cc::ContextProvider>
-RenderWidgetCompositor::OffscreenContextProvider() {
-  return RenderThreadImpl::current()->OffscreenCompositorContextProvider();
-}
-
 void RenderWidgetCompositor::RateLimitSharedMainThreadContext() {
   cc::ContextProvider* provider =
       RenderThreadImpl::current()->SharedMainThreadContextProvider().get();
   provider->Context3d()->rateLimitOffscreenContextCHROMIUM();
 }
 
 }  // namespace content