Move WebMouseEvent into its own header file.

content/public/test/render_view_test.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 CONTENT_PUBLIC_TEST_RENDER_VIEW_TEST_H_
 #define CONTENT_PUBLIC_TEST_RENDER_VIEW_TEST_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 16 matching lines @@
 
 namespace base {
 class FieldTrialList;
 }
 
 namespace blink {
 namespace scheduler {
 class RendererScheduler;
 }
 class WebInputElement;
+class WebMouseEvent;
 class WebWidget;
 }
 
 namespace gfx {
 class Rect;
 }
 
 namespace content {
 class ContentBrowserClient;
 class ContentClient;
@@ skipping 168 matching lines @@
   std::unique_ptr<base::mac::ScopedNSAutoreleasePool> autorelease_pool_;
 #endif
 
  private:
   void GoToOffset(int offset, const GURL& url, const PageState& state);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_TEST_RENDER_VIEW_TEST_H_