Do not set the mouse event handler if Widget::SetCapture() fails

ui/views/widget/desktop_aura/desktop_window_tree_host_win.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 "ui/views/widget/desktop_aura/desktop_window_tree_host_win.h"
 
 #include "base/win/metro.h"
 #include "third_party/skia/include/core/SkPath.h"
 #include "third_party/skia/include/core/SkRegion.h"
 #include "ui/aura/client/aura_constants.h"
@@ skipping 667 matching lines @@
   return GetWidget()->widget_delegate() &&
       GetWidget()->widget_delegate()->ExecuteWindowsCommand(command);
 }
 
 void DesktopWindowTreeHostWin::HandleCancelMode() {
   dispatcher()->DispatchCancelModeEvent();
 }
 
 void DesktopWindowTreeHostWin::HandleCaptureLost() {
   OnHostLostWindowCapture();
-  native_widget_delegate_->OnMouseCaptureLost();
 }
 
 void DesktopWindowTreeHostWin::HandleClose() {
   GetWidget()->Close();
 }
 
 bool DesktopWindowTreeHostWin::HandleCommand(int command) {
   return GetWidget()->widget_delegate()->ExecuteWindowsCommand(command);
 }
 
@@ skipping 244 matching lines @@
 
 // static
 DesktopWindowTreeHost* DesktopWindowTreeHost::Create(
     internal::NativeWidgetDelegate* native_widget_delegate,
     DesktopNativeWidgetAura* desktop_native_widget_aura) {
   return new DesktopWindowTreeHostWin(native_widget_delegate,
                                       desktop_native_widget_aura);
 }
 
 }  // namespace views