[Mac][MC] Initial accessibility pass.

ui/message_center/cocoa/status_item_view.mm

 // Copyright (c) 2013 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.
 
 #import "ui/message_center/cocoa/status_item_view.h"
 
 #include <cmath>
 
 #include "base/format_macros.h"
 #include "grit/ui_resources.h"
@@ skipping 132 matching lines @@
 
   // Draw the unread count.
   NSAttributedString* countString = [self unreadCountString];
   if (countString) {
     NSPoint countPoint = NSMakePoint(
         NSMaxX(drawRect) + kUnreadCountPadding, kUnreadCountMinY);
     [countString drawAtPoint:countPoint];
   }
 }
 
+- (NSArray*)accessibilityActionNames {
+  return @[ NSAccessibilityPressAction ];
+}
+
+- (void)accessibilityPerformAction:(NSString*)action {
+  if ([action isEqualToString:NSAccessibilityPressAction]) {
+    if (callback_)
+      callback_.get()();
+    return;
+  }
+  [super accessibilityPerformAction:action];
+}
+
 // Private /////////////////////////////////////////////////////////////////////
 
 - (BOOL)shouldHighlight {
   return highlight_ || inMouseEventSequence_;
 }
 
 - (NSAttributedString*)unreadCountString {
   if (unreadCount_ == 0)
     return nil;
 
   NSString* count = nil;
   if (unreadCount_ > 9)
     count = @"9+";
   else
     count = [NSString stringWithFormat:@"%"PRIuS, unreadCount_];
 
   NSColor* fontColor = [self shouldHighlight] ? [NSColor whiteColor]
                                               : [NSColor blackColor];
   NSDictionary* attributes = @{
       NSFontAttributeName: [NSFont fontWithName:@"Helvetica-Bold" size:12],
       NSForegroundColorAttributeName: fontColor,
   };
   return [[[NSAttributedString alloc] initWithString:count
                                           attributes:attributes] autorelease];
 }
 
 @end