[Android] Suspend shared timers for hidden renderers

components/scheduler/renderer/renderer_scheduler.h

 // Copyright 2014 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.
 
 #ifndef COMPONENTS_SCHEDULER_RENDERER_RENDERER_SCHEDULER_H_
 #define COMPONENTS_SCHEDULER_RENDERER_RENDERER_SCHEDULER_H_
 
 #include "base/message_loop/message_loop.h"
 #include "components/scheduler/child/child_scheduler.h"
 #include "components/scheduler/child/single_thread_idle_task_runner.h"
@@ skipping 61 matching lines @@
   // process have been hidden. The renderer is assumed to be visible when the
   // scheduler is constructed. Must be called on the main thread.
   virtual void OnRendererHidden() = 0;
 
   // Tells the scheduler that at least one render widget managed by this
   // renderer process has become visible and the renderer is no longer hidden.
   // The renderer is assumed to be visible when the scheduler is constructed.
   // Must be called on the main thread.
   virtual void OnRendererVisible() = 0;
 
+  // Tells the scheduler that the renderer process has been backgrounded, i.e.,
+  // there are no critical, user facing activities (visual, audio, etc...)
+  // driven by this process. A stricter condition than |OnRendererHidden()|, the
+  // process is assumed to be foregrounded when the scheduler is constructed.
+  // Must be called on the main thread.
+  virtual void OnRendererBackgrounded() = 0;
+
+  // Tells the scheduler that the renderer process has been foregrounded.
+  // This is the assumed state when the scheduler is constructed.
+  // Must be called on the main thread.
+  virtual void OnRendererForegrounded() = 0;
+
   // Tells the scheduler that a page load has started.  The scheduler will
   // prioritize loading tasks for a short duration afterwards.
   // Must be called from the main thread.
   virtual void OnPageLoadStarted() = 0;
 
   // Returns true if the scheduler has reason to believe that high priority work
   // may soon arrive on the main thread, e.g., if gesture events were observed
   // recently.
   // Must be called from the main thread.
   virtual bool IsHighPriorityWorkAnticipated() = 0;
 
   // Suspends the timer queue and increments the timer queue suspension count.
   // May only be called from the main thread.
   virtual void SuspendTimerQueue() = 0;
 
   // Decrements the timer queue suspension count and re-enables the timer queue
   // if the suspension count is zero and the current schduler policy allows it.
   virtual void ResumeTimerQueue() = 0;
 
+  // Sets whether to allow suspension of timers after the backgrounded signal is
+  // received via OnRendererBackgrounded. Defaults to disabled.
+  virtual void SetTimerQueueSuspensionWhenBackgroundedEnabled(bool enabled) = 0;
+
  protected:
   RendererScheduler();
   DISALLOW_COPY_AND_ASSIGN(RendererScheduler);
 };
 
 }  // namespace scheduler
 
 #endif  // COMPONENTS_SCHEDULER_RENDERER_RENDERER_SCHEDULER_H_