RenderWidget side compositor scheduling logic

This moves the compositor scheduling suppression logic out to RenderWidget /
RenderWidgetCompositor so we don't have to bounce through WebKit just to do
this. The suppression logic is needed to avoid producing unwanted frames during
page transitions when in single-threaded compositing mode which will often be
white flashes and which slow down the page cycler benchmarks.

This implements WebKit API that will be added by https://bugs.webkit.org/show_bug.cgi?id=110640.
This patch will compile before that patch lands and rolls, but will introduce
page cycler regressions and flashes.

BUG=


Review URL: https://chromiumcodereview.appspot.com/12319076

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@184826 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 26 insertions, 4 deletions

diff --git a/content/renderer/gpu/render_widget_compositor.cc b/content/renderer/gpu/render_widget_compositor.cc
index b602930..5534f18 100644
--- a/content/renderer/gpu/render_widget_compositor.cc
+++ b/content/renderer/gpu/render_widget_compositor.cc
@@ -214,12 +214,26 @@ scoped_ptr<RenderWidgetCompositor> RenderWidgetCompositor::Create(
 
 RenderWidgetCompositor::RenderWidgetCompositor(
     RenderWidget* widget, WebKit::WebLayerTreeViewClient* client)
-  : widget_(widget),
+  : suppress_schedule_composite_(false),
+    widget_(widget),
     client_(client) {
 }
 
 RenderWidgetCompositor::~RenderWidgetCompositor() {}
 
+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::initialize(cc::LayerTreeSettings settings) {
   scoped_ptr<cc::Thread> impl_thread;
   CompositorThread* compositor_thread =
@@ -434,10 +448,9 @@ void RenderWidgetCompositor::didCompleteSwapBuffers() {
   widget_->didCompleteSwapBuffers();
 }
 
-// TODO(jamesr): This goes through WebViewImpl just to do suppression, refactor
-// that piece out.
 void RenderWidgetCompositor::scheduleComposite() {
-  client_->scheduleComposite();
+  if (!suppress_schedule_composite_)
+    widget_->scheduleComposite();
 }
 
 class RenderWidgetCompositor::MainThreadContextProvider
diff --git a/content/renderer/gpu/render_widget_compositor.h b/content/renderer/gpu/render_widget_compositor.h
index ea1a0f5..ccf84e3 100644
--- a/content/renderer/gpu/render_widget_compositor.h
+++ b/content/renderer/gpu/render_widget_compositor.h
@@ -30,6 +30,8 @@ class RenderWidgetCompositor : public WebKit::WebLayerTreeView,
 
   cc::LayerTreeHost* layer_tree_host() const { return layer_tree_host_.get(); }
 
+  void SetSuppressScheduleComposite(bool suppress);
+
   // WebLayerTreeView implementation.
   virtual void setSurfaceReady();
   virtual void setRootLayer(const WebKit::WebLayer& layer);
@@ -95,6 +97,7 @@ private:
   bool initialize(cc::LayerTreeSettings settings);
 
   bool threaded_;
+  bool suppress_schedule_composite_;
   RenderWidget* widget_;
   WebKit::WebLayerTreeViewClient* client_;
   scoped_ptr<cc::LayerTreeHost> layer_tree_host_;
diff --git a/content/renderer/render_widget.cc b/content/renderer/render_widget.cc
index b8982cc..a7cf437 100644
--- a/content/renderer/render_widget.cc
+++ b/content/renderer/render_widget.cc
@@ -1354,6 +1354,11 @@ WebKit::WebLayerTreeView* RenderWidget::layerTreeView() {
   return compositor_.get();
 }
 
+void RenderWidget::suppressCompositorScheduling(bool enable) {
+  if (compositor_)
+    compositor_->SetSuppressScheduleComposite(enable);
+}
+
 void RenderWidget::willBeginCompositorFrame() {
   TRACE_EVENT0("gpu", "RenderWidget::willBeginCompositorFrame");
 
diff --git a/content/renderer/render_widget.h b/content/renderer/render_widget.h
index a9c6ba7..503e3d7 100644
--- a/content/renderer/render_widget.h
+++ b/content/renderer/render_widget.h
@@ -117,6 +117,7 @@ class CONTENT_EXPORT RenderWidget
   virtual bool Send(IPC::Message* msg) OVERRIDE;
 
   // WebKit::WebWidgetClient
+  virtual void suppressCompositorScheduling(bool enable);
   virtual void willBeginCompositorFrame();
   virtual void didInvalidateRect(const WebKit::WebRect&);
   virtual void didScrollRect(int dx, int dy,