Remove GestureEvent interface, and rename GestureEventImpl to GestureEvent.

ui/views/events/event_aura.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/events/event.h"
 
 #include "base/logging.h"
 #include "ui/base/event.h"
 #include "ui/base/keycodes/keyboard_code_conversion.h"
 
@@ skipping 35 matching lines @@
     : MouseEvent(native_event) {
   CHECK(ui::GetScrollOffsets(
       native_event->native_event(), &x_offset_, &y_offset_));
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // GestureEvent, public:
 
 GestureEvent::GestureEvent(const NativeEvent& event)
     : LocatedEvent(event),
-      details_(static_cast<ui::GestureEventImpl*>(event)->details()) {
+      details_(static_cast<ui::GestureEvent*>(event)->details()) {
 }
 
 }  // namespace views