Revert of Plugin Power Saver: Remove Size Recheck hack in plugin placeholders.

components/plugins/renderer/loadable_plugin_placeholder.h

Index: components/plugins/renderer/loadable_plugin_placeholder.h
diff --git a/components/plugins/renderer/loadable_plugin_placeholder.h b/components/plugins/renderer/loadable_plugin_placeholder.h
index 5cddaed00057c80bdbde6243a6fc97caf1dac516..bc5114e45b7ba1d7a79d534fffc75f673401f743 100644
--- a/components/plugins/renderer/loadable_plugin_placeholder.h
+++ b/components/plugins/renderer/loadable_plugin_placeholder.h
@@ -88,6 +88,7 @@
   void UpdateMessage();
 
   bool LoadingBlocked() const;
+  void RecheckSizeAndMaybeUnthrottle();
 
   // Plugin creation is embedder-specific.
   virtual blink::WebPlugin* CreatePlugin() = 0;
@@ -119,7 +120,10 @@
   bool finished_loading_;
   std::string identifier_;
 
+  // Used to prevent re-entrancy during the size recheck for throttled plugins.
+  bool in_size_recheck_;
   gfx::Rect unobscured_rect_;
+  base::OneShotTimer size_update_timer_;
 
   // True if the power saver heuristic has already been run on this content.
   bool heuristic_run_before_;