Prevent VoiceOver from announcing omnibox overlay windows.

While typing into the omnibox, VoiceOver will announce
"untitled window created"
This is fairly disruptive and has been commented on by users.
We should revisit how to make the underlying NSMatrix accessible, but in the meantime, set the window to NSAccessibilityUnknownRole so VoiceOver will ignore it.

Similarly, status bubbles cause VoiceOver to announce "untitled window created". The content contained therein is exposed in other ways to the user of VoiceOver.

BUG=63483
TEST=manual


Review URL: http://codereview.chromium.org/7982033

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@102207 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/ui/cocoa/omnibox/omnibox_popup_view_mac.mm

@@ -344,6 +344,10 @@ void OmniboxPopupViewMac::CreatePopupIfNeeded() {
 
     [contentView addSubview:matrix];
     [popup_ setContentView:contentView];
+
+    // TODO(dtseng): Ignore until we provide NSAccessibility support.
+    [popup_ accessibilitySetOverrideValue:NSAccessibilityUnknownRole
+        forAttribute:NSAccessibilityRoleAttribute];
   }
 }
 

chrome/browser/ui/cocoa/status_bubble_mac.mm

@@ -377,6 +377,10 @@ void StatusBubbleMac::Create() {
 
   [window_ setAlphaValue:0.0];
 
+  // TODO(dtseng): Ignore until we provide NSAccessibility support.
+  [window_ accessibilitySetOverrideValue:NSAccessibilityUnknownRole
+      forAttribute:NSAccessibilityRoleAttribute];
+
   // Set a delegate for the fade-in and fade-out transitions to be notified
   // when fades are complete.  The ownership model is for window_ to own
   // animation_dictionary, which owns animation, which owns