Fix progress bar indicator for accessibility.

ui/message_center/cocoa/notification_controller.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/notification_controller.h"
 
 #include <algorithm>
 
 #include "base/mac/foundation_util.h"
 #include "base/strings/string_util.h"
@@ skipping 33 matching lines @@
 
   if (progressFraction == 0.0)
     return;
 
   path = [NSBezierPath bezierPathWithRoundedRect:sliceRect
       xRadius:message_center::kProgressBarCornerRadius
       yRadius:message_center::kProgressBarCornerRadius];
   [gfx::SkColorToCalibratedNSColor(message_center::kProgressBarSliceColor) set];
   [path fill];
 }
+
+- (id)accessibilityAttributeValue:(NSString*)attribute {
+  double progressValue = 0.0;
+  if ([attribute isEqualToString:NSAccessibilityDescriptionAttribute]) {
+    progressValue = [self doubleValue];
+  } else if ([attribute isEqualToString:NSAccessibilityMinValueAttribute]) {
+    progressValue = [self minValue];
+  } else if ([attribute isEqualToString:NSAccessibilityMaxValueAttribute]) {
+    progressValue = [self maxValue];
+  } else {
+    return [super accessibilityAttributeValue:attribute];
+  }
+
+  return [NSString stringWithFormat:@"%lf", progressValue];
+}
 @end
 
 ////////////////////////////////////////////////////////////////////////////////
 @interface MCNotificationButton : NSButton
 @end
 
 @implementation MCNotificationButton
 // drawRect: needs to fill the button with a background, otherwise we don't get
 // subpixel antialiasing.
 - (void)drawRect:(NSRect)dirtyRect {
@@ skipping 782 matching lines @@
                    forFont:(NSFont*)nsfont
           maxNumberOfLines:(size_t)lines {
   size_t unused;
   return [self wrapText:text
                 forFont:nsfont
        maxNumberOfLines:lines
             actualLines:&unused];
 }
 
 @end