Plugin Power Saver: Unthrottle dynamically sized plugins correctly.

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 7683ba7c6d8a081c1c7116859c449a061552a52c..a741cc082d4c36bc5209f00b5567c90ff0a2557c 100644
--- a/components/plugins/renderer/loadable_plugin_placeholder.h
+++ b/components/plugins/renderer/loadable_plugin_placeholder.h
@@ -85,6 +85,9 @@ class LoadablePluginPlaceholder : public PluginPlaceholder {
   void PluginDestroyed() override;
   v8::Local<v8::Object> GetV8ScriptableObject(
       v8::Isolate* isolate) const override;
+#if defined(ENABLE_PLUGINS)

[groby-ooo-7-16, 2015/06/11 23:32:56]

Question - why do we need to ENABLE_PLUGINS for *parts* of the plugin
placeholder? Shouldn't the PPH not exist if we don't have plugins?

[tommycli, 2015/06/11 23:39:21]

Because previously a ChromePluginPlaceholder was used on Android also even
though ENABLE_PLUGINS is false.

This was lame and finally addressed by this refactor:
https://codereview.chromium.org/1161923004/

Now LoadablePluginPlaceholder and ChromePluginPlaceholder are only compiled if
ENABLE_PLUGINS is on, and these ifdefs have been removed

+  void OnUnobscuredSizeUpdate(const gfx::Size& unobscured_size) override;
+#endif
 
   // RenderFrameObserver methods:
   void WasShown() override;
@@ -97,6 +100,9 @@ class LoadablePluginPlaceholder : public PluginPlaceholder {
   void UpdateMessage();
 
   bool LoadingBlocked() const;
+#if defined(ENABLE_PLUGINS)
+  void RecheckSizeAndMaybeUnthrottle();
+#endif
 
   // Plugin creation is embedder-specific.
   virtual blink::WebPlugin* CreatePlugin() = 0;
@@ -129,6 +135,14 @@ class LoadablePluginPlaceholder : public PluginPlaceholder {
   bool finished_loading_;
   std::string identifier_;
 
+  // Used to prevent re-entrancy during the size recheck for throttled plugins.
+  bool in_size_recheck_;
+  gfx::Size unobscured_size_;
+
+  // A separate weak factory so we can schedule, coalesce and cancel unthrottle
+  // calls due to plugin size updates.
+  base::WeakPtrFactory<LoadablePluginPlaceholder> size_update_weak_factory_;
+
   base::WeakPtrFactory<LoadablePluginPlaceholder> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(LoadablePluginPlaceholder);