MacViews: Fix accessibility hit tests, provide AXTitle

ui/accessibility/platform/ax_platform_node_mac.mm

 // Copyright 2014 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/accessibility/platform/ax_platform_node_mac.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/strings/sys_string_conversions.h"
 #import "ui/accessibility/ax_node_data.h"
@@ skipping 226 matching lines @@
 - (NSString*)AXRole {
   if (!node_)
     return nil;
   return [[self class] nativeRoleFromAXRole:node_->GetData().role];
 }
 
 - (NSValue*)AXSize {
   return [NSValue valueWithSize:self.boundsInScreen.size];
 }
 
+- (NSString*)AXTitle {
+  std::string value;
+  if (node_->GetStringAttribute(ui::AX_ATTR_NAME, &value))
+    return base::SysUTF8ToNSString(value);
+  return nil;
+}
+
 // NSAccessibility informal protocol implementation.
 
 - (BOOL)accessibilityIsIgnored {
   return [[self AXRole] isEqualToString:NSAccessibilityUnknownRole];
 }
 
 - (id)accessibilityHitTest:(NSPoint)point {
   for (AXPlatformNodeCocoa* child in [self AXChildren]) {
     if (NSPointInRect(point, child.boundsInScreen))
       return [child accessibilityHitTest:point];
   }
   return NSAccessibilityUnignoredAncestor(self);
 }
 
 - (NSArray*)accessibilityActionNames {
   return nil;
 }
 
 - (NSArray*)accessibilityAttributeNames {
   return @[
     NSAccessibilityChildrenAttribute,
     NSAccessibilityParentAttribute,
     NSAccessibilityPositionAttribute,
     NSAccessibilityRoleAttribute,
     NSAccessibilitySizeAttribute,
+
+    // Always add title. Cocoa asks for it regardless of it appearing in here,

[dmazzoni, 2015/03/06 07:58:01]

Rather than a comment for "title", I'd maybe just put a comment at the top
saying "these attributes are required on all accessibility objects" - later
we'll add more below that are optional.

[tapted, 2015/03/06 11:01:18]

Done. Added the comment at top.

The comment on Title didn't really capture what was "weird" about what Cocoa was
doing, so I've updated it to say "Title is required for most elements. Cocoa
asks for the value even if it is omitted here, but won't present it to
accessibility APIs without this."

I think we could just add it optionally too after checking
node_->HasStringAttribute(ui::AX_ATTR_NAME) and everything would still work
fine. (And maybe that's better -- happy to change it). But it felt inconsistent
to unconditionally give an answer to AXTitle, and plenty of Apple's own UI seems
to do it this way (i.e. present the attribute name, but return <nil> if there's
nothing appropriate).

Either way, easy to move down to the optional segment when this is fleshed out
more :)

+    // most things should have it, and it's OK to return nil.
+    NSAccessibilityTitleAttribute,
   ];
+  // TODO(tapted): Add additional attributes based on role.
 }
 
 - (BOOL)accessibilityIsAttributeSettable:(NSString*)attribute {
   return NO;
 }
 
 - (id)accessibilityAttributeValue:(NSString*)attribute {
   SEL selector = NSSelectorFromString(attribute);
   if ([self respondsToSelector:selector])
     return [self performSelector:selector];
@@ skipping 33 matching lines @@
 void AXPlatformNodeMac::NotifyAccessibilityEvent(ui::AXEvent event_type) {
   // TODO(dmazzoni): implement this.  http://crbug.com/396137
 }
 
 int AXPlatformNodeMac::GetIndexInParent() {
   // TODO(dmazzoni): implement this.  http://crbug.com/396137
   return -1;
 }
 
 }  // namespace ui