Bug 32658 – Make it easier for plug-ins to participate in the Accessibility hierarchy

• Status: RESOLVED
• Resolution: WONTFIX
• Component: Plug-ins

[Sven-S. Porst]

A plug-in should participate in the accessibility hierarchy.

To do that it needs to supply an AXParent element to -accessibilityAttributeValue:.

Finding the correct element for that seems unnecessarily hard as the NSView subclassed by the plug-in seems to be contained in another element in the accessibility hierarchy which is not easily accessed:

Accessibility Inspector shows:

<AXApplication: "Safari">
 <AXWindow: "YouTube - Hampe Recycling Werbung (Kino)">
  <AXGroup>
   <AXScrollArea>
    <AXWebArea: "HTML-Inhalt">
     <AXGroup: "Blocked Flash content">          ← mystery element I have to reference
      <AXGroup: "Blocked Flash content">         ← plug-in's element

I should return the 'mystery' AXGroup as the plug-in's AXParent element to keep the accessibility hierarchy intact, but it doesn't seem to be returned by any convenient method.

Instead I had to resort to looping through all elements on the page and some speculation, giving code like this to find the desired object:

id value = nil;
id webArea = [[[self superview] accessibilityAttributeValue:NSAccessibilityChildrenAttribute] objectAtIndex:0];
	NSArray * webAreaChildren = [webArea accessibilityAttributeValue:NSAccessibilityChildrenAttribute];
	CTFForEachObject( NSObject , child, webAreaChildren ) { // looping macro
		NSArray * subChildren = [child accessibilityAttributeValue:NSAccessibilityChildrenAttribute];
		if ([subChildren count] == 1) {
			id firstSubChild = [[child accessibilityAttributeValue:NSAccessibilityChildrenAttribute] objectAtIndex:0];
			if ( firstSubChild == self ) {
				value = child;
				break;
			}
		}
	}
return value;

This seems all of non-obvious, non-elegant and not particularly efficient to me. Perhaps WebKit could assist plug-ins a bit more in being good accessibility citizens and provide a method returning the relevant object.

[Mark Rowe (bdash)]

<rdar://problem/7483304>

[Alexey Proskuryakov]

Mass closing plug-in bugs, as plug-in support has been removed from WebKit.

Please comment and/or reopen if this still affects WebKit in some way.