Makes RenderFrameObserver/RenderViewObserver::OnDestruct pure virtual.

chrome/renderer/banners/app_banner_client.cc

 // Copyright 2015 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 "chrome/renderer/banners/app_banner_client.h"
 
 #include "chrome/common/render_messages.h"
 #include "ipc/ipc_message.h"
 #include "third_party/WebKit/public/platform/WebString.h"
 
 using blink::WebString;
 
 AppBannerClient::AppBannerClient(content::RenderFrame* render_frame)
     : content::RenderFrameObserver(render_frame) {
 }
 
 AppBannerClient::~AppBannerClient() {
 }
 
-void AppBannerClient::OnDestruct() {
-  // The RenderFrameImpl destructor calls RenderFrameObserver::OnDestruct, which
-  // deletes this object. However, RenderFrameImpl also holds a scoped pointer
-  // to AppBannerClient. Override OnDestruct to be a no-op to stop a double call
-  // to the destructor and a renderer crash.
-}
+void AppBannerClient::OnDestruct() {}
 
 bool AppBannerClient::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(AppBannerClient, message)
     IPC_MESSAGE_HANDLER(ChromeViewMsg_AppBannerAccepted, OnBannerAccepted);
     IPC_MESSAGE_HANDLER(ChromeViewMsg_AppBannerDismissed, OnBannerDismissed);
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
 }
@@ skipping 25 matching lines @@
 void AppBannerClient::OnBannerAccepted(int request_id,
                                         const std::string& platform) {
   ResolveEvent(request_id, platform,
                blink::WebAppBannerPromptResult::Outcome::Accepted);
 }
 
 void AppBannerClient::OnBannerDismissed(int request_id) {
   ResolveEvent(request_id, "",
                blink::WebAppBannerPromptResult::Outcome::Dismissed);
 }