Notify Blink to suppress frame requests during BeginMainFrame

content/renderer/render_widget.cc

Index: content/renderer/render_widget.cc
diff --git a/content/renderer/render_widget.cc b/content/renderer/render_widget.cc
index f071205065d09b9a5c0807f35c58408049906a6d..fad713688537ced1e7c778e959517428cf7cc926 100644
--- a/content/renderer/render_widget.cc
+++ b/content/renderer/render_widget.cc
@@ -912,6 +912,8 @@ void RenderWidget::DidCommitCompositorFrame() {
     observer.DidCommitCompositorFrame();
   for (auto& observer : render_frame_proxies_)
     observer.DidCommitCompositorFrame();
+
+  GetWebWidget()->setSuppressFrameRequestsWorkaroundFor704763Only(false);

[esprehn, 2017/04/04 06:13:55]

I think should be in RenderWidget::UpdateVisualState() right after the call to
updateAllLifecyclePhases, I don't think it's safe to suppress updates after that
call, it'd leave unscheduled work.

Doing it between WillBeginCompositorFrame and UpdateVisualState means it's
between these lines:

https://cs.chromium.org/chromium/src/cc/trees/proxy_main.cc?type=cs&l=178

and

https://cs.chromium.org/chromium/src/cc/trees/proxy_main.cc?type=cs&l=189

which seems okay.

[alancutter (OOO until 2018), 2017/04/04 09:54:31]

Fair call, moving the unset back to suggested place.
Keeping a DCHECK there to catch if it's ever missed.

 }
 
 void RenderWidget::DidCompletePageScaleAnimation() {}
@@ -959,6 +961,8 @@ void RenderWidget::UpdateVisualState() {
 void RenderWidget::WillBeginCompositorFrame() {
   TRACE_EVENT0("gpu", "RenderWidget::willBeginCompositorFrame");
 
+  GetWebWidget()->setSuppressFrameRequestsWorkaroundFor704763Only(true);
+
   // The UpdateTextInputState can result in further layout and possibly
   // enable GPU acceleration so they need to be called before any painting
   // is done.