Don't rewrite events twice.

ui/aura/window_tree_host.cc

 // Copyright (c) 2013 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/window_tree_host.h"
 
 #include "base/command_line.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/trace_event/trace_event.h"
 #include "cc/base/switches.h"
@@ skipping 181 matching lines @@
   DCHECK(!input_method_);
   input_method_ = input_method;
   owned_input_method_ = false;
 }
 
 ui::EventDispatchDetails WindowTreeHost::DispatchKeyEventPostIME(
     ui::KeyEvent* event) {
   // If dispatch to IME is already disabled we shouldn't reach here.
   DCHECK(!dispatcher_->should_skip_ime());
   dispatcher_->set_skip_ime(true);
-  ui::EventDispatchDetails dispatch_details = SendEventToSink(event);
+  // We should bypass event rewriters here as they've been tried before.
+  ui::EventDispatchDetails dispatch_details =
+      event_sink()->OnEventFromSource(event);
   if (!dispatch_details.dispatcher_destroyed)
     dispatcher_->set_skip_ime(false);
   return dispatch_details;
 }
 
 void WindowTreeHost::Show() {
   // Ensure that compositor has been properly initialized, see InitCompositor()
   // and InitHost().
   DCHECK(compositor());
   DCHECK_EQ(compositor()->root_layer(), window()->layer());
@@ skipping 142 matching lines @@
   client::CursorClient* cursor_client = client::GetCursorClient(window());
   if (cursor_client) {
     const display::Display& display =
         display::Screen::GetScreen()->GetDisplayNearestWindow(window());
     cursor_client->SetDisplay(display);
   }
   dispatcher()->OnCursorMovedToRootLocation(root_location);
 }
 
 }  // namespace aura