Turn off accessibility access to notification images.

ui/message_center/cocoa/notification_controller.mm

Index: ui/message_center/cocoa/notification_controller.mm
diff --git a/ui/message_center/cocoa/notification_controller.mm b/ui/message_center/cocoa/notification_controller.mm
index d2c8bf387c78655c690a77bcf9826822d38d9dc8..c58d45b47bad08abf34e9d03a43c5cb4a978138c 100644
--- a/ui/message_center/cocoa/notification_controller.mm
+++ b/ui/message_center/cocoa/notification_controller.mm
@@ -203,10 +203,24 @@
 @interface AccessibilityIgnoredBox : NSBox
 @end
 
+// Ignore this element, but expose its children to accessibility.

[dewittj, 2014/06/12 21:02:27]

This comment seems out of date?

[Pete Williamson, 2014/06/17 17:36:36]

Hmm, not sure how to change this to make it better.  That is in fact what this
method does, but the other method makes the kids not appear.  In the future we
will remove the other method, but this method will remain, and its comment will
remain valid.

Can you think of a wording that makes more sense to you?

[dewittj, 2014/06/17 17:45:01]

The problem is partly that the comment is above the @implementation line, not
the - (BOOL)accessibilityIsIgnored line, making it a comment that applies to the
whole interface.

I'd say move the comment up to line 202, where it can document the
AccessibilityIgnoredBox, and fully describe the behavior.  Then between lines
207 and 208 you can describe that this function alone does not cause children to
be ignored.

 @implementation AccessibilityIgnoredBox
 - (BOOL)accessibilityIsIgnored {
   return YES;
 }
+
+// Pretend this element has no children.
+// TODO(petewil): Until we have alt text available, we will hide the children of
+//  the box also.  Remove this override once alt text is set (by using
+// NSAccessibilityDescriptionAttribute).
+- (id)accessibilityAttributeValue:(NSString*)attribute {
+  // If we get a request for NSAccessibilityChildrenAttribute, return an empty
+  // array to pretend we have no children.
+  if ([attribute isEqualToString:NSAccessibilityChildrenAttribute])
+    return @[];
+  else
+    return [super accessibilityAttributeValue:attribute];
+}
 @end
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -297,8 +311,7 @@
   [rootView addSubview:closeButton_];
 
   // Create the small image.
-  [self configureSmallImageInFrame:rootFrame];
-  [[self view] addSubview:smallImage_];
+  [rootView addSubview:[self createSmallImageInFrame:rootFrame]];

[dewittj, 2014/06/12 21:02:27]

Any reason you diverged from the prevailing style here?

[self configureFoo];
[rootView addSubview:fooView_];

[Pete Williamson, 2014/06/17 17:36:35]

I was following the same pattern that the Icon view used:
[rootView addSubview:[self createIconView]];

We're really doing a create now, not a configure, so I thought it made more
sense to follow the createIconView pattern.  I'm happy to change both if you
like. 

[dewittj, 2014/06/17 17:45:01]

Okay I see better now why it's different.  sounds ok

 
   NSRect contentFrame = [self currentContentRect];
 
@@ -732,17 +745,33 @@
                        forAttribute:NSAccessibilityTitleAttribute];
 }
 
-- (void)configureSmallImageInFrame:(NSRect)rootFrame {
+- (NSView*)createSmallImageInFrame:(NSRect)rootFrame {
   int smallImageXOffset =
       message_center::kSmallImagePadding + message_center::kSmallImageSize;
-  NSRect smallImageFrame =
+  NSRect boxFrame =
       NSMakeRect(NSMaxX(rootFrame) - smallImageXOffset,
                  NSMinY(rootFrame) + message_center::kSmallImagePadding,
                  message_center::kSmallImageSize,
                  message_center::kSmallImageSize);
+
+  // Put the smallImage inside another box which can hide it from accessibility
+  // until we have some alt text to go with it.  Once we have alt text, remove
+  // the box, and set NSAccessibilityDescriptionAttribute with it.
+  base::scoped_nsobject<NSBox> imageBox(
+      [[AccessibilityIgnoredBox alloc] initWithFrame:boxFrame]);
+  [self configureCustomBox:imageBox];
+  [imageBox setAutoresizingMask:NSViewMinYMargin];
+
+  NSRect smallImageFrame =
+      NSMakeRect(0,0,

[Robert Sesek, 2014/06/12 18:19:48]

nit: space after first 0,

[Pete Williamson, 2014/06/17 17:36:35]

Done.

+                 message_center::kSmallImageSize,
+                 message_center::kSmallImageSize);
+
   smallImage_.reset([[NSImageView alloc] initWithFrame:smallImageFrame]);
   [smallImage_ setImageScaling:NSImageScaleProportionallyUpOrDown];
-  [smallImage_ setAutoresizingMask:NSViewMinYMargin];
+  [imageBox setContentView:smallImage_];
+
+  return imageBox.autorelease();
 }
 
 - (void)configureTitleInFrame:(NSRect)contentFrame {