Share backing canvases between browser compositors.

content/browser/compositor/gpu_process_transport_factory.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 "content/browser/compositor/gpu_process_transport_factory.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 90 matching lines @@
     : next_surface_id_namespace_(1u),
       task_graph_runner_(new cc::TaskGraphRunner),
       callback_factory_(this) {
   if (UseSurfacesEnabled())
     surface_manager_ = make_scoped_ptr(new cc::SurfaceManager);
 
   if (ui::IsUIImplSidePaintingEnabled()) {
     raster_thread_.reset(new RasterThread(task_graph_runner_.get()));
     raster_thread_->Start();
   }
+#if defined(OS_WIN)
+  software_backing_.reset(new OutputDeviceBacking);
+#endif
 }
 
 GpuProcessTransportFactory::~GpuProcessTransportFactory() {
   DCHECK(per_compositor_data_.empty());
 
   // Make sure the lost context callback doesn't try to run during destruction.
   callback_factory_.InvalidateWeakPtrs();
 
   task_graph_runner_->Shutdown();
   if (raster_thread_)
     raster_thread_->Join();
 }
 
 scoped_ptr<WebGraphicsContext3DCommandBufferImpl>
 GpuProcessTransportFactory::CreateOffscreenCommandBufferContext() {
   CauseForGpuLaunch cause =
       CAUSE_FOR_GPU_LAUNCH_WEBGRAPHICSCONTEXT3DCOMMANDBUFFERIMPL_INITIALIZE;
   scoped_refptr<GpuChannelHost> gpu_channel_host(
       BrowserGpuChannelHostFactory::instance()->EstablishGpuChannelSync(cause));
   return CreateContextCommon(gpu_channel_host, 0);
 }
 
-scoped_ptr<cc::SoftwareOutputDevice> CreateSoftwareOutputDevice(
+scoped_ptr<cc::SoftwareOutputDevice>
+GpuProcessTransportFactory::CreateSoftwareOutputDevice(
     ui::Compositor* compositor) {
 #if defined(OS_WIN)
-  return scoped_ptr<cc::SoftwareOutputDevice>(new SoftwareOutputDeviceWin(
-      compositor));
+  return scoped_ptr<cc::SoftwareOutputDevice>(
+      new SoftwareOutputDeviceWin(software_backing_.get(), compositor));
 #elif defined(USE_OZONE)
   return scoped_ptr<cc::SoftwareOutputDevice>(new SoftwareOutputDeviceOzone(
       compositor));
 #elif defined(USE_X11)
   return scoped_ptr<cc::SoftwareOutputDevice>(new SoftwareOutputDeviceX11(
       compositor));
 #elif defined(OS_MACOSX)
   return scoped_ptr<cc::SoftwareOutputDevice>(
       new SoftwareOutputDeviceMac(compositor));
 #else
@@ skipping 451 matching lines @@
   FOR_EACH_OBSERVER(ImageTransportFactoryObserver,
                     observer_list_,
                     OnLostResources());
 
   // Kill things that use the shared context before killing the shared context.
   lost_gl_helper.reset();
   lost_shared_main_thread_contexts  = NULL;
 }
 
 }  // namespace content