Fix a few lingering bugs in BrowserAccessibilityManager and BrowserAccessibilityCocoa.

content/browser/accessibility/browser_accessibility_cocoa.mm

Index: content/browser/accessibility/browser_accessibility_cocoa.mm
diff --git a/content/browser/accessibility/browser_accessibility_cocoa.mm b/content/browser/accessibility/browser_accessibility_cocoa.mm
index b6b08ea2cbeb08e40b5e1f663b5defdee4223ecf..9ba206b13b83c4628fcbebb6ff0cb1b2171cd6c3 100644
--- a/content/browser/accessibility/browser_accessibility_cocoa.mm
+++ b/content/browser/accessibility/browser_accessibility_cocoa.mm
@@ -16,6 +16,10 @@
 #include "grit/webkit_strings.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebRect.h"
 
+// See http://openradar.appspot.com/9896491. This has been tested on 10.5,
+// 10.6, and 10.7.
+extern "C" void NSAccessibilityUnregisterUniqueIdForUIElement(id element);
+
 typedef WebAccessibility::IntAttribute IntAttribute;
 typedef WebAccessibility::StringAttribute StringAttribute;
 
@@ -247,6 +251,7 @@ NSDictionary* attributeToMethodNameMap = nil;
 // Deletes our associated BrowserAccessibilityMac.
 - (void)dealloc {
   if (browserAccessibility_) {
+    NSAccessibilityUnregisterUniqueIdForUIElement(self);
     delete browserAccessibility_;
     browserAccessibility_ = NULL;
   }
@@ -830,5 +835,9 @@ NSDictionary* attributeToMethodNameMap = nil;
   return browserAccessibility_->renderer_id();
 }
 
+- (BOOL)accessibilityShouldUseUniqueId {
+  return YES;
+}
+
 @end