Remove PluginLoadObserver and related logic, it was only used for NPAPI.

content/renderer/pepper/pepper_webplugin_impl.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_RENDERER_PEPPER_PEPPER_WEBPLUGIN_IMPL_H_
 #define CONTENT_RENDERER_PEPPER_PEPPER_WEBPLUGIN_IMPL_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 44 matching lines @@
   void updateFocus(bool focused, blink::WebFocusType focus_type) override;
   void updateVisibility(bool visible) override;
   bool acceptsInputEvents() override;
   blink::WebInputEventResult handleInputEvent(
       const blink::WebInputEvent& event,
       blink::WebCursorInfo& cursor_info) override;
   void didReceiveResponse(const blink::WebURLResponse& response) override;
   void didReceiveData(const char* data, int data_length) override;
   void didFinishLoading() override;
   void didFailLoading(const blink::WebURLError&) override;
-  void didFinishLoadingFrameRequest(const blink::WebURL& url,
-                                    void* notify_data) override;
-  void didFailLoadingFrameRequest(const blink::WebURL& url,
-                                  void* notify_data,
-                                  const blink::WebURLError& error) override;
   bool hasSelection() const override;
   blink::WebString selectionAsText() const override;
   blink::WebString selectionAsMarkup() const override;
   blink::WebURL linkAtPosition(const blink::WebPoint& position) const override;
   bool getPrintPresetOptionsFromDocument(
       blink::WebPrintPresetOptions* preset_options) override;
   bool startFind(const blink::WebString& search_text,
                  bool case_sensitive,
                  int identifier) override;
   void selectFindResult(bool forward) override;
@@ skipping 25 matching lines @@
   PP_Var instance_object_;
   blink::WebPluginContainer* container_;
   base::WeakPtrFactory<PepperWebPluginImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PepperWebPluginImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_PEPPER_PEPPER_WEBPLUGIN_IMPL_H_