Fix a regression caused by the background fullscreen handling code.

ui/views/win/hwnd_message_handler.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/win/hwnd_message_handler.h"
 
 #include <dwmapi.h>
 #include <oleacc.h>
 #include <shellapi.h>
 #include <tchar.h>
@@ skipping 1096 matching lines @@
     tme.dwHoverTime = 0;
     TrackMouseEvent(&tme);
   } else if (mouse_tracking_flags != active_mouse_tracking_flags_) {
     TrackMouseEvents(active_mouse_tracking_flags_ | TME_CANCEL);
     TrackMouseEvents(mouse_tracking_flags);
   }
 }
 
 void HWNDMessageHandler::ClientAreaSizeChanged() {
   // Ignore size changes due to fullscreen windows losing activation.
-  if (background_fullscreen_hack_)
+  if (background_fullscreen_hack_ && !sent_window_size_changing_)
     return;
   gfx::Size s = GetClientAreaBounds().size();
   delegate_->HandleClientSizeChanged(s);
 }
 
 bool HWNDMessageHandler::GetClientAreaInsets(gfx::Insets* insets) const {
   if (delegate_->GetClientAreaInsets(insets))
     return true;
   DCHECK(insets->IsEmpty());
 
@@ skipping 1612 matching lines @@
   MONITORINFO monitor_info = {sizeof(monitor_info)};
   GetMonitorInfo(MonitorFromWindow(hwnd(), MONITOR_DEFAULTTOPRIMARY),
                  &monitor_info);
   gfx::Rect shrunk_rect(monitor_info.rcMonitor);
   shrunk_rect.set_height(shrunk_rect.height() - 1);
   background_fullscreen_hack_ = true;
   SetBoundsInternal(shrunk_rect, false);
 }
 
 }  // namespace views