Makes RenderFrameObserver/RenderViewObserver::OnDestruct pure virtual.

content/renderer/render_view_mouse_lock_dispatcher.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 "content/renderer/render_view_mouse_lock_dispatcher.h"
 
 #include "content/common/view_messages.h"
 #include "content/renderer/render_view_impl.h"
 #include "third_party/WebKit/public/web/WebFrame.h"
 #include "third_party/WebKit/public/web/WebUserGestureIndicator.h"
@@ skipping 31 matching lines @@
   IPC_BEGIN_MESSAGE_MAP(RenderViewMouseLockDispatcher, message)
     IPC_MESSAGE_HANDLER(ViewMsg_LockMouse_ACK, OnLockMouseACK)
     IPC_MESSAGE_FORWARD(ViewMsg_MouseLockLost,
                         static_cast<MouseLockDispatcher*>(this),
                         MouseLockDispatcher::OnMouseLockLost)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
 }
 
+void RenderViewMouseLockDispatcher::OnDestruct() {
+  delete this;
+}
+
 void RenderViewMouseLockDispatcher::OnLockMouseACK(bool succeeded) {
   // Notify the base class.
   MouseLockDispatcher::OnLockMouseACK(succeeded);
 
   // Mouse Lock removes the system cursor and provides all mouse motion as
   // .movementX/Y values on events all sent to a fixed target. This requires
   // content to specifically request the mode to be entered.
   // Mouse Capture is implicitly given for the duration of a drag event, and
   // sends all mouse events to the initial target of the drag.
   // If Lock is entered it supercedes any in progress Capture.
   if (succeeded && render_view_impl_->GetWidget()->webwidget())
     render_view_impl_->GetWidget()->webwidget()->mouseCaptureLost();
 }
 
 }  // namespace content