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

content/renderer/browser_plugin/browser_plugin.cc

 // Copyright 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.
 
 #include "content/renderer/browser_plugin/browser_plugin.h"
 
 #include "base/command_line.h"
 #include "base/location.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 555 matching lines @@
 }
 
 void BrowserPlugin::didFinishLoading() {
   if (delegate_)
     delegate_->DidFinishLoading();
 }
 
 void BrowserPlugin::didFailLoading(const blink::WebURLError& error) {
 }
 
-void BrowserPlugin::didFinishLoadingFrameRequest(const blink::WebURL& url,
-                                                 void* notify_data) {
-}
-
-void BrowserPlugin::didFailLoadingFrameRequest(
-    const blink::WebURL& url,
-    void* notify_data,
-    const blink::WebURLError& error) {
-}
-
 bool BrowserPlugin::executeEditCommand(const blink::WebString& name) {
   BrowserPluginManager::Get()->Send(new BrowserPluginHostMsg_ExecuteEditCommand(
       browser_plugin_instance_id_,
       name.utf8()));
 
   // BrowserPlugin swallows edit commands.
   return true;
 }
 
 bool BrowserPlugin::executeEditCommand(const blink::WebString& name,
@@ skipping 65 matching lines @@
 bool BrowserPlugin::HandleMouseLockedInputEvent(
     const blink::WebMouseEvent& event) {
   BrowserPluginManager::Get()->Send(
       new BrowserPluginHostMsg_HandleInputEvent(browser_plugin_instance_id_,
                                                 view_rect_,
                                                 &event));
   return true;
 }
 
 }  // namespace content