Notify Blink to suppress frame requests during BeginMainFrame

content/renderer/render_widget.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/renderer/render_widget.h"
 
 #include <memory>
 #include <utility>
 
 #include "base/auto_reset.h"
@@ skipping 894 matching lines @@
 
   // Notify subclasses that we initiated the paint operation.
   DidInitiatePaint();
 }
 
 void RenderWidget::DidCommitCompositorFrame() {
   for (auto& observer : render_frames_)
     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() {}
 
 void RenderWidget::DidReceiveCompositorFrameAck() {
   TRACE_EVENT0("renderer", "RenderWidget::DidReceiveCompositorFrameAck");
 
   if (!next_paint_flags_ && !need_update_rect_for_auto_resize_) {
     return;
   }
@@ skipping 27 matching lines @@
 
   time_to_first_active_paint_recorded_ = true;
   base::TimeDelta sample = base::TimeTicks::Now() - was_shown_time_;
   UMA_HISTOGRAM_TIMES("PurgeAndSuspend.Experimental.TimeToFirstActivePaint",
                       sample);
 }
 
 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.
   UpdateTextInputState();
   UpdateSelectionBounds();
 
   for (auto& observer : render_frame_proxies_)
     observer.WillBeginCompositorFrame();
 }
 
@@ skipping 1366 matching lines @@
     // browser side (https://crbug.com/669219).
     // If there is no WebFrameWidget, then there will be no
     // InputMethodControllers for a WebLocalFrame.
     return nullptr;
   }
   return static_cast<blink::WebFrameWidget*>(GetWebWidget())
       ->getActiveWebInputMethodController();
 }
 
 }  // namespace content