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

content/child/npapi/webplugin_delegate_impl.h

Index: content/child/npapi/webplugin_delegate_impl.h
diff --git a/content/child/npapi/webplugin_delegate_impl.h b/content/child/npapi/webplugin_delegate_impl.h
index 72f559a9b1dd286edc1d57aeef70286e64bf62ab..9d75082bd1125ac27ae8f57d9b1f05f304150e63 100644
--- a/content/child/npapi/webplugin_delegate_impl.h
+++ b/content/child/npapi/webplugin_delegate_impl.h
@@ -92,41 +92,7 @@ class WebPluginDelegateImpl : public WebPluginDelegate {
   NPObject* GetPluginScriptableObject() override;
   NPP GetPluginNPP() override;
   bool GetFormValue(base::string16* value) override;
-  void DidFinishLoadWithReason(const GURL& url,
-                               NPReason reason,
-                               int notify_id) override;
   int GetProcessId() override;
-  void SendJavaScriptStream(const GURL& url,
-                            const std::string& result,
-                            bool success,
-                            int notify_id) override;
-  void DidReceiveManualResponse(const GURL& url,
-                                const std::string& mime_type,
-                                const std::string& headers,
-                                uint32 expected_length,
-                                uint32 last_modified) override;
-  void DidReceiveManualData(const char* buffer, int length) override;
-  void DidFinishManualLoading() override;
-  void DidManualLoadFail() override;
-  WebPluginResourceClient* CreateResourceClient(unsigned long resource_id,
-                                                const GURL& url,
-                                                int notify_id) override;
-  WebPluginResourceClient* CreateSeekableResourceClient(
-      unsigned long resource_id,
-      int range_request_id) override;
-  void FetchURL(unsigned long resource_id,
-                int notify_id,
-                const GURL& url,
-                const GURL& first_party_for_cookies,
-                const std::string& method,
-                const char* buf,
-                unsigned int len,
-                const Referrer& referrer,
-                bool notify_redirects,
-                bool is_plugin_src_load,
-                int origin_pid,
-                int render_frame_id,
-                int render_view_id) override;
   // End of WebPluginDelegate implementation.
 
   gfx::PluginWindowHandle windowed_handle() const { return windowed_handle_; }