Makes RenderFrameObserver/RenderViewObserver::OnDestruct pure virtual.

android_webview/renderer/aw_render_view_ext.cc

 // 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.
 
 #include "android_webview/renderer/aw_render_view_ext.h"
 #include "android_webview/common/render_view_messages.h"
 #include "content/public/renderer/render_frame.h"
 #include "content/public/renderer/render_view.h"
 #include "third_party/WebKit/public/web/WebFrame.h"
 #include "third_party/WebKit/public/web/WebView.h"
@@ skipping 11 matching lines @@
 }
 
 void AwRenderViewExt::DidCommitCompositorFrame() {
   PostCheckContentsSize();
 }
 
 void AwRenderViewExt::DidUpdateLayout() {
   PostCheckContentsSize();
 }
 
+void AwRenderViewExt::OnDestruct() {
+  delete this;
+}
+
 void AwRenderViewExt::PostCheckContentsSize() {
   if (check_contents_size_timer_.IsRunning())
     return;
 
   check_contents_size_timer_.Start(FROM_HERE,
       base::TimeDelta::FromMilliseconds(0), this,
       &AwRenderViewExt::CheckContentsSize);
 }
 
 void AwRenderViewExt::CheckContentsSize() {
@@ skipping 24 matching lines @@
 
   if (contents_size == last_sent_contents_size_)
     return;
 
   last_sent_contents_size_ = contents_size;
   main_render_frame->Send(new AwViewHostMsg_OnContentsSizeChanged(
       main_render_frame->GetRoutingID(), contents_size));
 }
 
 }  // namespace android_webview