content: Cleanup class/struct forward declarations

content/browser/accessibility/browser_accessibility_manager_auralinux.h

 // Copyright (c) 2015 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_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_MANAGER_AURALINUX_H_
 #define CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_MANAGER_AURALINUX_H_
 
 #include "base/macros.h"
 #include "content/browser/accessibility/browser_accessibility_manager.h"
 
-struct ViewHostMsg_AccessibilityNotification_Params;
-
 namespace content {
 class BrowserAccessibilityAuraLinux;
 
 // Manages a tree of BrowserAccessibilityAuraLinux objects.
 class CONTENT_EXPORT BrowserAccessibilityManagerAuraLinux
     : public BrowserAccessibilityManager {
  public:
   BrowserAccessibilityManagerAuraLinux(
       AtkObject* parent_object,
       const ui::AXTreeUpdate& initial_tree,
@@ skipping 17 matching lines @@
 
   // Give BrowserAccessibilityManager::Create access to our constructor.
   friend class BrowserAccessibilityManager;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserAccessibilityManagerAuraLinux);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_MANAGER_AURALINUX_H_