Add support for GYP_DEFINES aura_wm=1 which also defines views_compositor=1.

aura/desktop_host_win.cc

 // Copyright (c) 2011 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 "aura/desktop_host_win.h"
 
 #include "aura/desktop.h"
 #include "aura/event.h"
 #include "base/message_loop.h"
 
@@ skipping 39 matching lines @@
 void DesktopHostWin::OnClose() {
   // TODO: this obviously shouldn't be here.
   MessageLoopForUI::current()->Quit();
 }
 
 LRESULT DesktopHostWin::OnMouseRange(UINT message,
                                      WPARAM w_param,
                                      LPARAM l_param) {
   MSG msg = { hwnd(), message, w_param, l_param, 0,
               { GET_X_LPARAM(l_param), GET_Y_LPARAM(l_param) } };
-  SetMsgHandled(desktop_->OnMouseEvent(MouseEvent(msg)));
+  MouseEvent event(msg);
+  bool handled = false;
+  if (!(event.flags() & ui::EF_IS_NON_CLIENT))
+    handled = desktop_->OnMouseEvent(event);
+  SetMsgHandled(handled);
   return 0;
 }
 
 void DesktopHostWin::OnPaint(HDC dc) {
   if (desktop_)
     desktop_->Draw();
   ValidateRect(hwnd(), NULL);
 }
 
 }  // namespace aura