events: Change gesture-event handler in EventHandler to not return any values.

ui/views/widget/native_widget_aura.h

 // 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.
 
 #ifndef UI_VIEWS_WIDGET_NATIVE_WIDGET_AURA_H_
 #define UI_VIEWS_WIDGET_NATIVE_WIDGET_AURA_H_
 
 #include "base/memory/scoped_vector.h"
 #include "base/memory/weak_ptr.h"
 #include "ui/aura/client/activation_delegate.h"
@@ skipping 139 matching lines @@
   virtual void OnWindowTargetVisibilityChanged(bool visible) OVERRIDE;
   virtual bool HasHitTestMask() const OVERRIDE;
   virtual void GetHitTestMask(gfx::Path* mask) const OVERRIDE;
   virtual scoped_refptr<ui::Texture> CopyTexture() OVERRIDE;
 
   // Overridden from ui::EventHandler:
   virtual ui::EventResult OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
   virtual ui::EventResult OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
   virtual ui::EventResult OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
   virtual ui::EventResult OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
-  virtual ui::EventResult OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
+  virtual void OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
   // Overridden from aura::client::ActivationDelegate:
   virtual bool ShouldActivate() const OVERRIDE;
   virtual void OnActivated() OVERRIDE;
   virtual void OnLostActive() OVERRIDE;
 
   // Overridden from aura::client::DragDropDelegate:
   virtual void OnDragEntered(const ui::DropTargetEvent& event) OVERRIDE;
   virtual int OnDragUpdated(const ui::DropTargetEvent& event) OVERRIDE;
   virtual void OnDragExited() OVERRIDE;
@@ skipping 37 matching lines @@
 
   scoped_ptr<DropHelper> drop_helper_;
   int last_drop_operation_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeWidgetAura);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIDGET_NATIVE_WIDGET_AURA_H_