Experimental 'purging and suspending' backgrounded tabs behind the flag

components/scheduler/renderer/renderer_scheduler.h

Index: components/scheduler/renderer/renderer_scheduler.h
diff --git a/components/scheduler/renderer/renderer_scheduler.h b/components/scheduler/renderer/renderer_scheduler.h
index 16f4770ccf36e17c4e3a1ccb964ec23bc22ea6da..51ed4b18f2c1003774f1e4398762285b52c1f02e 100644
--- a/components/scheduler/renderer/renderer_scheduler.h
+++ b/components/scheduler/renderer/renderer_scheduler.h
@@ -129,6 +129,11 @@ class SCHEDULER_EXPORT RendererScheduler : public ChildScheduler {
   // Must be called on the main thread.
   virtual void OnRendererForegrounded() = 0;
 
+  // Tells the scheduler that the render process should be suspended. This can
+  // only be done when the renderer is backgrounded. The renderer will be
+  // automatically resumed when foregrounded.
+  virtual void SuspendRenderer() = 0;
+
   // Tells the scheduler that a navigation task is pending. While any main-frame
   // navigation tasks are pending, the scheduler will ensure that loading tasks
   // are not blocked even if they are expensive. Must be called on the main