Make SingleThreadProxy a SchedulerClient

content/renderer/gpu/render_widget_compositor.cc

Index: content/renderer/gpu/render_widget_compositor.cc
diff --git a/content/renderer/gpu/render_widget_compositor.cc b/content/renderer/gpu/render_widget_compositor.cc
index dc007a2fc87a6b2efc38c64b2966e0f3d81bcda1..571ca264d0505b83a812a3311044290cd748e04c 100644
--- a/content/renderer/gpu/render_widget_compositor.cc
+++ b/content/renderer/gpu/render_widget_compositor.cc
@@ -279,6 +279,8 @@ scoped_ptr<RenderWidgetCompositor> RenderWidgetCompositor::Create(
       cmd->HasSwitch(cc::switches::kEnablePinchVirtualViewport);
   settings.allow_antialiasing &=
       !cmd->HasSwitch(cc::switches::kDisableCompositedAntialiasing);
+  settings.single_thread_proxy_scheduler =
+      !cmd->HasSwitch(switches::kDisableSingleThreadProxyScheduler);
 
   // These flags should be mirrored by UI versions in ui/compositor/.
   settings.initial_debug_state.show_debug_borders =
@@ -411,7 +413,6 @@ scoped_ptr<RenderWidgetCompositor> RenderWidgetCompositor::Create(
 RenderWidgetCompositor::RenderWidgetCompositor(RenderWidget* widget,
                                                bool threaded)
     : threaded_(threaded),
-      suppress_schedule_composite_(false),
       widget_(widget) {
 }
 
@@ -422,19 +423,6 @@ RenderWidgetCompositor::GetInputHandler() {
   return layer_tree_host_->GetInputHandler();
 }
 
-void RenderWidgetCompositor::SetSuppressScheduleComposite(bool suppress) {
-  if (suppress_schedule_composite_ == suppress)
-    return;
-
-  if (suppress)
-    TRACE_EVENT_ASYNC_BEGIN0(
-        "gpu", "RenderWidgetCompositor::SetSuppressScheduleComposite", this);
-  else
-    TRACE_EVENT_ASYNC_END0(
-        "gpu", "RenderWidgetCompositor::SetSuppressScheduleComposite", this);
-  suppress_schedule_composite_ = suppress;
-}
-
 bool RenderWidgetCompositor::BeginMainFrameRequested() const {
   return layer_tree_host_->BeginMainFrameRequested();
 }
@@ -547,7 +535,10 @@ void RenderWidgetCompositor::Initialize(cc::LayerTreeSettings settings) {
 }
 
 void RenderWidgetCompositor::setSurfaceReady() {
-  layer_tree_host_->SetLayerTreeHostClientReady();
+  // In tests without a RenderThreadImpl, don't set ready as this kicks
+  // off creating output surfaces that the test can't create.
+  if (RenderThreadImpl::current())
+    layer_tree_host_->SetLayerTreeHostClientReady();
 }
 
 void RenderWidgetCompositor::setRootLayer(const blink::WebLayer& layer) {
@@ -701,9 +692,9 @@ void RenderWidgetCompositor::compositeAndReadbackAsync(
       cc::CopyOutputRequest::CreateBitmapRequest(
           base::Bind(&CompositeAndReadbackAsyncCallback, callback));
   layer_tree_host_->root_layer()->RequestCopyOfOutput(request.Pass());
-  if (!threaded_) {
-    widget_->webwidget()->animate(0.0);
-    widget_->webwidget()->layout();
+
+  if (!threaded_ &&
+      !layer_tree_host_->settings().single_thread_proxy_scheduler) {
     layer_tree_host_->Composite(gfx::FrameTime::Now());
   }
 }
@@ -800,11 +791,6 @@ void RenderWidgetCompositor::DidCompleteSwapBuffers() {
     widget_->OnSwapBuffersComplete();
 }
 
-void RenderWidgetCompositor::ScheduleComposite() {
-  if (!suppress_schedule_composite_)
-    widget_->scheduleComposite();
-}
-
 void RenderWidgetCompositor::ScheduleAnimation() {
   widget_->scheduleAnimation();
 }