Refactor PluginService to take PluginList as a dependency.

content/browser/plugin_service.h

Index: content/browser/plugin_service.h
diff --git a/content/browser/plugin_service.h b/content/browser/plugin_service.h
index 6be2c4f3623da48ed3d5fab10ca438be07473a8b..a637103de43561dbe7a0aa7b0200fe42fe2ae43b 100644
--- a/content/browser/plugin_service.h
+++ b/content/browser/plugin_service.h
@@ -154,11 +154,11 @@ class CONTENT_EXPORT PluginService
 
   // Asynchronously loads plugins if necessary and then calls back to the
   // provided function on the calling MessageLoop on completion.
-  void GetPlugins(const GetPluginsCallback& callback);
+  virtual void GetPlugins(const GetPluginsCallback& callback);
 
   // Asynchronously loads the list of plugin groups if necessary and then calls
   // back to the provided function on the calling MessageLoop on completion.
-  void GetPluginGroups(const GetPluginGroupsCallback& callback);
+  virtual void GetPluginGroups(const GetPluginGroupsCallback& callback);
 
   // Tells all the renderer processes associated with the given browser context
   // to throw away their cache of the plugin list, and optionally also reload
@@ -173,7 +173,6 @@ class CONTENT_EXPORT PluginService
   }
   content::PluginServiceFilter* filter() { return filter_; }
 
-
   // The following functions are wrappers around webkit::npapi::PluginList.
   // These must be used instead of those in order to ensure that we have a
   // single global list in the component build and so that we don't
@@ -189,13 +188,15 @@ class CONTENT_EXPORT PluginService
   // TODO(dpranke): This should be private.
   webkit::npapi::PluginList* plugin_list();
 
+ protected:
+  // Creates the PluginService object, but the actual plugin list is generated
+  // lazily. In tests, use MockPluginList for dependency injection.
+  PluginService(webkit::npapi::PluginList* plugin_list);
+  virtual ~PluginService();
+
  private:
   friend struct DefaultSingletonTraits<PluginService>;
-
-  // Creates the PluginService object, but doesn't actually build the plugin
-  // list yet.  It's generated lazily.
-  PluginService();
-  virtual ~PluginService();
+  friend struct PluginServiceSingletonTraits;
 
   // base::WaitableEventWatcher::Delegate implementation.
   virtual void OnWaitableEventSignaled(base::WaitableEvent* waitable_event);
@@ -245,6 +246,9 @@ class CONTENT_EXPORT PluginService
       base::files::FilePathWatcher::Delegate* delegate);
 #endif
 
+  // The plugin list instance.
+  webkit::npapi::PluginList* plugin_list_;
+
   // The browser's UI locale.
   const std::string ui_locale_;