Cleaning up compositing field trial code and enable FCM in beta/stable

content/browser/renderer_host/render_widget_host_impl.cc

Index: content/browser/renderer_host/render_widget_host_impl.cc
diff --git a/content/browser/renderer_host/render_widget_host_impl.cc b/content/browser/renderer_host/render_widget_host_impl.cc
index 3b93544dbc9bd8efccc9bd2e4549160fc561c4dd..9651a7ca16eb198e5285807c6e5c2609970e5846 100644
--- a/content/browser/renderer_host/render_widget_host_impl.cc
+++ b/content/browser/renderer_host/render_widget_host_impl.cc
@@ -35,6 +35,7 @@
 #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/compositor_util.h"
 #include "content/public/common/content_constants.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/result_codes.h"
@@ -171,6 +172,8 @@ RenderWidgetHostImpl::RenderWidgetHostImpl(RenderWidgetHostDelegate* delegate,
     DCHECK(surface_id_);
   }
 
+  is_threaded_compositing_enabled_ = IsThreadedCompositingEnabled();
+
   process_->Attach(this, routing_id_);
   // Because the widget initializes as is_hidden_ == false,
   // tell the process host that we're alive.
@@ -1898,18 +1901,7 @@ void RenderWidgetHostImpl::AcknowledgeBufferPresent(
 }
 
 void RenderWidgetHostImpl::AcknowledgeSwapBuffersToRenderer() {
-  base::FieldTrial* trial =
-      base::FieldTrialList::Find(content::kGpuCompositingFieldTrialName);
-  bool is_thread_trial = trial && trial->group_name() ==
-      content::kGpuCompositingFieldTrialThreadEnabledName;
-  bool has_enable = CommandLine::ForCurrentProcess()->HasSwitch(
-      switches::kEnableThreadedCompositing);
-  bool has_disable = CommandLine::ForCurrentProcess()->HasSwitch(
-      switches::kDisableThreadedCompositing);
-  DCHECK(!is_thread_trial || !has_disable);
-  bool enable_threaded_compositing =
-      is_thread_trial || (has_enable && !has_disable);
-  if (!enable_threaded_compositing)
+  if (!is_threaded_compositing_enabled_)
     Send(new ViewMsg_SwapBuffers_ACK(routing_id_));
 }