Add threaded compositing mode to field trial

content/browser/renderer_host/render_widget_host_impl.cc

 // Copyright (c) 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 "content/browser/renderer_host/render_widget_host_impl.h"
 
 #include <utility>
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
 #include "base/i18n/rtl.h"
 #include "base/message_loop.h"
+#include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "base/string_number_conversions.h"
 #include "base/utf_string_conversions.h"
 #include "content/browser/gpu/gpu_process_host.h"
 #include "content/browser/gpu/gpu_process_host_ui_shim.h"
 #include "content/browser/gpu/gpu_surface_tracker.h"
 #include "content/browser/renderer_host/backing_store.h"
 #include "content/browser/renderer_host/backing_store_manager.h"
 #include "content/browser/renderer_host/render_process_host_impl.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
 #include "content/browser/renderer_host/render_widget_helper.h"
 #include "content/browser/renderer_host/render_widget_host_delegate.h"
 #include "content/browser/renderer_host/tap_suppression_controller.h"
 #include "content/common/accessibility_messages.h"
 #include "content/common/gpu/gpu_messages.h"
 #include "content/common/view_messages.h"
 #include "content/port/browser/render_widget_host_view_port.h"
 #include "content/port/browser/smooth_scroll_gesture.h"
 #include "content/public/browser/native_web_keyboard_event.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_types.h"
 #include "content/public/browser/user_metrics.h"
+#include "content/public/common/content_constants.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/result_codes.h"
 #include "skia/ext/image_operations.h"
 #include "skia/ext/platform_canvas.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebCompositionUnderline.h"
 #if defined(OS_WIN)
 #include "third_party/WebKit/Source/WebKit/chromium/public/win/WebScreenInfoFactory.h"
 #endif
 #include "ui/base/keycodes/keyboard_codes.h"
 #include "ui/gfx/skbitmap_operations.h"
@@ skipping 1839 matching lines @@
 // static
 void RenderWidgetHostImpl::AcknowledgeBufferPresent(
     int32 route_id, int gpu_host_id, uint32 sync_point) {
   GpuProcessHostUIShim* ui_shim = GpuProcessHostUIShim::FromID(gpu_host_id);
   if (ui_shim)
     ui_shim->Send(new AcceleratedSurfaceMsg_BufferPresented(route_id,
                                                             sync_point));
 }
 
 void RenderWidgetHostImpl::AcknowledgeSwapBuffersToRenderer() {
-  bool enable_threaded_compositing =
-      CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kEnableThreadedCompositing) &&
-      !CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kDisableThreadedCompositing);
+  base::FieldTrial* trial =
+      base::FieldTrialList::Find(content::kGpuCompositingFieldTrialName);
+  bool thread_trial = trial && trial->group_name() ==
+      content::kGpuCompositingFieldTrialThreadEnabledName;
+  bool enable_threaded_compositing = thread_trial ||
+      (CommandLine::ForCurrentProcess()->HasSwitch(
+           switches::kEnableThreadedCompositing) &&
+       !CommandLine::ForCurrentProcess()->HasSwitch(
+           switches::kDisableThreadedCompositing));
   if (!enable_threaded_compositing)
     Send(new ViewMsg_SwapBuffers_ACK(routing_id_));
 }
 
 void RenderWidgetHostImpl::DelayedAutoResized() {
   gfx::Size new_size = new_auto_size_;
   // Clear the new_auto_size_ since the empty value is used as a flag to
   // indicate that no callback is in progress (i.e. without this line
   // DelayedAutoResized will not get called again).
   new_auto_size_.SetSize(0, 0);
   if (!should_auto_resize_)
     return;
 
   OnRenderAutoResized(new_size);
 }
 
 }  // namespace content