Remove mouse events from Sky

sky/engine/core/html/canvas/MouseEventHitRegion.h

-// Copyright 2014 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 SKY_ENGINE_CORE_HTML_CANVAS_MOUSEEVENTHITREGION_H_
-#define SKY_ENGINE_CORE_HTML_CANVAS_MOUSEEVENTHITREGION_H_
-
-#include "sky/engine/core/events/MouseEvent.h"
-#include "sky/engine/core/html/HTMLCanvasElement.h"
-#include "sky/engine/core/html/canvas/CanvasRenderingContext.h"
-#include "sky/engine/core/html/canvas/CanvasRenderingContext2D.h"
-
-namespace blink {
-
-class MouseEventHitRegion {
-public:
-    static String region(MouseEvent& event)
-    {
-        if (!event.target() || !isHTMLCanvasElement(event.target()->toNode()))
-            return String();
-
-        HTMLCanvasElement* canvas = toHTMLCanvasElement(event.target()->toNode());
-        CanvasRenderingContext* context = canvas->renderingContext();
-        if (!context || !context->is2d())
-            return String();
-
-        HitRegion* hitRegion = toCanvasRenderingContext2D(context)->
-            hitRegionAtPoint(LayoutPoint(event.offsetX(), event.offsetY()));
-
-        if (!hitRegion)
-            return String();
-
-        String id = hitRegion->id();
-        if (id.isEmpty())
-            return String();
-
-        return id;
-    }
-};
-
-} // namespace blink
-
-#endif  // SKY_ENGINE_CORE_HTML_CANVAS_MOUSEEVENTHITREGION_H_