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

content/plugin/webplugin_delegate_stub.h

Index: content/plugin/webplugin_delegate_stub.h
diff --git a/content/plugin/webplugin_delegate_stub.h b/content/plugin/webplugin_delegate_stub.h
index 63964e11555c31eaf604b499528c0b2c6af52e9a..e150661d27576a4335528f8d706403f31c0d4b9e 100644
--- a/content/plugin/webplugin_delegate_stub.h
+++ b/content/plugin/webplugin_delegate_stub.h
@@ -67,7 +67,6 @@ class WebPluginDelegateStub : public IPC::Listener,
                         int data_offset);
   void OnDidFinishLoading(int id);
   void OnDidFail(int id);
-  void OnDidFinishLoadWithReason(const GURL& url, int reason, int notify_id);
   void OnSetFocus(bool focused);
   void OnHandleInputEvent(const blink::WebInputEvent* event,
                           bool* handled, WebCursor* cursor);
@@ -75,10 +74,6 @@ class WebPluginDelegateStub : public IPC::Listener,
   void OnDidPaint();
   void OnUpdateGeometry(const PluginMsg_UpdateGeometry_Param& param);
   void OnGetPluginScriptableObject(int* route_id);
-  void OnSendJavaScriptStream(const GURL& url,
-                              const std::string& result,
-                              bool success,
-                              int notify_id);
   void OnGetFormValue(base::string16* value, bool* success);
 
   void OnSetContentAreaFocus(bool has_focus);
@@ -99,18 +94,6 @@ class WebPluginDelegateStub : public IPC::Listener,
   void OnImeCompositionCompleted(const base::string16& text);
 #endif
 
-  void OnDidReceiveManualResponse(
-      const GURL& url,
-      const PluginMsg_DidReceiveResponseParams& params);
-  void OnDidReceiveManualData(const std::vector<char>& buffer);
-  void OnDidFinishManualLoading();
-  void OnDidManualLoadFail();
-  void OnHandleURLRequestReply(unsigned long resource_id,
-                               const GURL& url,
-                               int notify_id);
-  void OnHTTPRangeRequestReply(unsigned long resource_id, int range_request_id);
-  void OnFetchURL(const PluginMsg_FetchURL_Params& params);
-
   std::string mime_type_;
   int instance_id_;