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..dcee76a62920766fe3f86024aa828938d36e790e 100644
--- a/components/scheduler/renderer/renderer_scheduler_impl.cc
+++ b/components/scheduler/renderer/renderer_scheduler_impl.cc
@@ -387,6 +387,14 @@ void RendererSchedulerImpl::OnRendererForegrounded() {
   ResumeTimerQueueWhenForegrounded();
 }
 
+void RendererSchedulerImpl::SuspendRendererWhenBackgrounded() {
+  helper_.CheckOnValidThread();
+  if (helper_.IsShutdown() || !MainThreadOnly().renderer_backgrounded)
+    return;
+  suspend_timers_when_backgrounded_closure_.Cancel();
+  SuspendTimerQueueWhenBackgrounded();
+}
+
 void RendererSchedulerImpl::EndIdlePeriod() {
   if (MainThreadOnly().in_idle_period_for_testing)
     return;