Fix a few lingering bugs in BrowserAccessibilityManager and BrowserAccessibilityCocoa.

content/browser/accessibility/browser_accessibility_cocoa.h

 // Copyright (c) 2011 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_COCOA_H_
 #define CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_COCOA_H_
 #pragma once
 
 #import <Cocoa/Cocoa.h>
 
 #import "base/memory/scoped_nsobject.h"
 #import "content/browser/accessibility/browser_accessibility_delegate_mac.h"
 #include "content/browser/accessibility/browser_accessibility.h"
 
 // BrowserAccessibilityCocoa is a cocoa wrapper around the BrowserAccessibility
 // object. The renderer converts webkit's accessibility tree into a
 // WebAccessibility tree and passes it to the browser process over IPC.
 // This class converts it into a format Cocoa can query.
-// Inheriting from NSView rather than NSObject as clients cannot add
-// observers to pure NSObject derived classes.
-@interface BrowserAccessibilityCocoa : NSView {
+@interface BrowserAccessibilityCocoa : NSObject {
  @private
   BrowserAccessibility* browserAccessibility_;
   scoped_nsobject<NSMutableArray> children_;
   id<BrowserAccessibilityDelegateCocoa> delegate_;
 }
 
 // This creates a cocoa browser accessibility object around
 // the cross platform BrowserAccessibility object.  The delegate is
 // used to communicate with the host renderer.  None of these
 // parameters can be null.
@@ skipping 35 matching lines @@
 @property(nonatomic, readonly) NSArray* tabs;
 @property(nonatomic, readonly) NSString* title;
 @property(nonatomic, readonly) NSString* url;
 @property(nonatomic, readonly) NSString* value;
 @property(nonatomic, readonly) NSValue* visibleCharacterRange;
 @property(nonatomic, readonly) NSNumber* visited;
 @property(nonatomic, readonly) id window;
 @end
 
 #endif // CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_COCOA_H_