Fix a few lingering bugs in BrowserAccessibilityManager and BrowserAccessibilityCocoa.

content/browser/accessibility/browser_accessibility_cocoa.h

Index: content/browser/accessibility/browser_accessibility_cocoa.h
diff --git a/content/browser/accessibility/browser_accessibility_cocoa.h b/content/browser/accessibility/browser_accessibility_cocoa.h
index ab4044f3ee0e02f044e9bf95db79f4c6d3b3f605..bf1134d4b3a694d724c61df7e36a6e9f5b5b41a8 100644
--- a/content/browser/accessibility/browser_accessibility_cocoa.h
+++ b/content/browser/accessibility/browser_accessibility_cocoa.h
@@ -16,9 +16,7 @@
 // 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_;