Introduce WebPluginContainerBase to abstract WebPluginContainerImpl.

third_party/WebKit/Source/web/WebHelperPluginImpl.h

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 24 matching lines @@
 #include "platform/wtf/Allocator.h"
 #include "platform/wtf/Noncopyable.h"
 #include "platform/wtf/RefPtr.h"
 #include "platform/wtf/text/WTFString.h"
 #include "public/web/WebHelperPlugin.h"
 
 namespace blink {
 
 class HTMLObjectElement;
 class WebLocalFrameBase;
-class WebPluginContainerImpl;
+class WebPluginContainerBase;
 
 // Utility class to host helper plugins for media. Internally, it creates a
 // detached HTMLPluginElement to host the plugin and uses
 // LocalFrameClient::createPlugin() to instantiate the requested plugin.
 class WebHelperPluginImpl final : public WebHelperPlugin {
   WTF_MAKE_NONCOPYABLE(WebHelperPluginImpl);
   USING_FAST_MALLOC(WebHelperPluginImpl);
 
  public:
   // WebHelperPlugin methods:
   WebPlugin* GetPlugin() override;
   void Destroy() override;
 
  private:
   friend class WebHelperPlugin;
 
   WebHelperPluginImpl();
 
   bool Initialize(const String& plugin_type, WebLocalFrameBase*);
   void ReallyDestroy(TimerBase*);
 
   Timer<WebHelperPluginImpl> destruction_timer_;
   Persistent<HTMLObjectElement> object_element_;
-  Persistent<WebPluginContainerImpl> plugin_container_;
+  Persistent<WebPluginContainerBase> plugin_container_;
 };
 
 }  // namespace blink
 
 #endif  // WebHelperPluginImpl_h