Explicitly coerce PostDispatchAction to uint32_t in DispatchEvent()

ui/views/widget/desktop_aura/desktop_screen_x11.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_screen_x11.h"
 
 #include <X11/extensions/Xrandr.h>
 #include <X11/Xlib.h>
 
 // It clashes with out RootWindow.
@@ skipping 228 matching lines @@
       configure_timer_->Start(
           FROM_HERE,
           base::TimeDelta::FromMilliseconds(kConfigureDelayMs),
           this,
           &DesktopScreenX11::ConfigureTimerFired);
     }
   } else {
     NOTREACHED();
   }
 
-  return ui::POST_DISPATCH_NONE;
+  return ui::kPostDispatchNone;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // DesktopScreenX11, private:
 
 DesktopScreenX11::DesktopScreenX11(
     const std::vector<gfx::Display>& test_displays)
     : xdisplay_(gfx::GetXDisplay()),
       x_root_window_(DefaultRootWindow(xdisplay_)),
       has_xrandr_(false),
@@ skipping 102 matching lines @@
   change_notifier_.NotifyDisplaysChanged(old_displays, displays_);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 
 gfx::Screen* CreateDesktopScreen() {
   return new DesktopScreenX11;
 }
 
 }  // namespace views