Experimental 'purging and suspending' backgrounded tabs behind the flag

components/scheduler/renderer/renderer_scheduler_impl.cc

Index: components/scheduler/renderer/renderer_scheduler_impl.cc
diff --git a/components/scheduler/renderer/renderer_scheduler_impl.cc b/components/scheduler/renderer/renderer_scheduler_impl.cc
index 3ae7991381cf6b59f152c4dbce6d4b3b2a3a95e5..7d9ef4ff7a8c31f4a4eb62a00b3027dd7d2e31ef 100644
--- a/components/scheduler/renderer/renderer_scheduler_impl.cc
+++ b/components/scheduler/renderer/renderer_scheduler_impl.cc
@@ -387,6 +387,15 @@ void RendererSchedulerImpl::OnRendererForegrounded() {
   ResumeTimerQueueWhenForegrounded();
 }
 
+void RendererSchedulerImpl::SuspendRenderer() {
+  helper_.CheckOnValidThread();
+  DCHECK(MainThreadOnly().renderer_backgrounded);
+  if (helper_.IsShutdown())
+    return;
+  suspend_timers_when_backgrounded_closure_.Cancel();

[Sami, 2016/05/12 11:31:35]

Could you add a TODO about possibly suspending other types of tasks too (e.g.,
loading tasks)?

[hajimehoshi, 2016/05/13 06:07:45]

Done.

+  SuspendTimerQueueWhenBackgrounded();
+}
+
 void RendererSchedulerImpl::EndIdlePeriod() {
   if (MainThreadOnly().in_idle_period_for_testing)
     return;