Create a new action triggered when a BeginMainFrame is not expected before vsync

third_party/WebKit/public/platform/scheduler/renderer/renderer_scheduler.h

Index: third_party/WebKit/public/platform/scheduler/renderer/renderer_scheduler.h
diff --git a/third_party/WebKit/public/platform/scheduler/renderer/renderer_scheduler.h b/third_party/WebKit/public/platform/scheduler/renderer/renderer_scheduler.h
index cdcc868078f2c7210366107cbcda478d1b52baf7..e0f5ac5f419dcc265a5fdb184cdbc490957fdb80 100644
--- a/third_party/WebKit/public/platform/scheduler/renderer/renderer_scheduler.h
+++ b/third_party/WebKit/public/platform/scheduler/renderer/renderer_scheduler.h
@@ -84,6 +84,12 @@ class BLINK_PLATFORM_EXPORT RendererScheduler : public ChildScheduler {
   // need to be drawn. Must be called from the main thread.
   virtual void BeginFrameNotExpectedSoon() = 0;
 
+  // Called to notify about the start of a period where main frames are not
+  // scheduled and so short idle work can be scheduled. This will precede
+  // BeginFrameNotExpectedSoon and is also called when the compositor is busy
+  // but the main thread is not.
+  virtual void BeginMainFrameNotExpectedUntil(const base::TimeTicks& time) = 0;

[Sami, 2017/04/06 17:39:09]

nit: pass by value

+
   // Called to notify about the start of a new frame.  Must be called from the
   // main thread.
   virtual void WillBeginFrame(const cc::BeginFrameArgs& args) = 0;