Apply Ash's key rewriter to an aura::MouseEvent so that Modifler+Click is handled correctly

ui/aura/dispatcher_linux.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/aura/dispatcher_linux.h"
 
 #include <X11/extensions/XInput2.h>
 
 #include "ui/base/events.h"
 
-namespace {
-
-// Pro-processes an XEvent before it is handled. The pre-processings include:
-// - Map Alt+Button1 to Button3
-void PreprocessXEvent(XEvent* xevent) {
-  if (!xevent || xevent->type != GenericEvent)
-    return;
-
-  XIDeviceEvent* xievent = static_cast<XIDeviceEvent*>(xevent->xcookie.data);
-  if ((xievent->evtype == XI_ButtonPress ||
-      xievent->evtype == XI_ButtonRelease) &&
-        (xievent->mods.effective & Mod1Mask) &&
-        xievent->detail == 1) {
-    xievent->mods.effective &= ~Mod1Mask;
-    xievent->detail = 3;
-    if (xievent->evtype == XI_ButtonRelease) {
-      // On the release clear the left button from the existing state and the
-      // mods, and set the right button.
-      XISetMask(xievent->buttons.mask, 3);
-      XIClearMask(xievent->buttons.mask, 1);
-      xievent->mods.effective &= ~Button1Mask;
-    }
-  }
-}
-
-}  // namespace
-
 namespace aura {
 
 DispatcherLinux::DispatcherLinux()
     : x_root_window_(
         DefaultRootWindow(base::MessagePumpAuraX11::GetDefaultXDisplay())) {
   base::MessagePumpAuraX11::SetDefaultDispatcher(this);
   MessageLoopForUI::current()->AddObserver(this);
 }
 
 DispatcherLinux::~DispatcherLinux() {
@@ skipping 54 matching lines @@
       (*it)->Dispatch(xev);
     }
     return true;
   }
   MessageLoop::Dispatcher* dispatcher = GetDispatcherForXEvent(xev);
   return dispatcher ? dispatcher->Dispatch(xev) : true;
 }
 
 base::EventStatus DispatcherLinux::WillProcessEvent(
     const base::NativeEvent& event) {
-  PreprocessXEvent(event);
   return base::EVENT_CONTINUE;
 }
 
 void DispatcherLinux::DidProcessEvent(const base::NativeEvent& event) {
 }
 
 MessageLoop::Dispatcher* DispatcherLinux::GetDispatcherForXEvent(
     XEvent* xev) const {
   ::Window x_window = xev->xany.window;
   if (xev->type == GenericEvent) {
     XIDeviceEvent* xievent = static_cast<XIDeviceEvent*>(xev->xcookie.data);
     x_window = xievent->event;
   }
   DispatchersMap::const_iterator it = dispatchers_.find(x_window);
   return it != dispatchers_.end() ? it->second : NULL;
 }
 
 MessageLoop::Dispatcher* CreateDispatcher() {
   return new DispatcherLinux;
 }
 
 }  // namespace aura