Mac a11y: Add RoleDescription and Value attributes to accessibility information.

ui/accessibility/platform/ax_platform_node_mac.mm

Index: ui/accessibility/platform/ax_platform_node_mac.mm
diff --git a/ui/accessibility/platform/ax_platform_node_mac.mm b/ui/accessibility/platform/ax_platform_node_mac.mm
index 620841889eae237edc5ee3a5a3f4f237f6de4a33..931a76be95c405137a30f21ffcdc0480d4a4c267 100644
--- a/ui/accessibility/platform/ax_platform_node_mac.mm
+++ b/ui/accessibility/platform/ax_platform_node_mac.mm
@@ -223,43 +223,6 @@ RoleMap BuildSubroleMap() {
   return gfx::ScreenRectToNSRect(node_->GetBoundsInScreen());
 }
 
-- (NSArray*)AXChildren {
-  if (!node_)
-    return nil;
-  int count = node_->GetChildCount();
-  NSMutableArray* children = [NSMutableArray arrayWithCapacity:count];
-  for (int i = 0; i < count; ++i)
-    [children addObject:node_->ChildAtIndex(i)];
-  return NSAccessibilityUnignoredChildren(children);
-}
-
-- (id)AXParent {
-  if (!node_)
-    return nil;
-  return NSAccessibilityUnignoredAncestor(node_->GetParent());
-}
-
-- (NSValue*)AXPosition {
-  return [NSValue valueWithPoint:self.boundsInScreen.origin];
-}
-
-- (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 {
@@ -290,6 +253,10 @@ RoleMap BuildSubroleMap() {
     // 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.
     NSAccessibilityTitleAttribute,
+
+    // Attributes which are not required, but are general to all roles.
+    NSAccessibilityRoleDescriptionAttribute,
+    NSAccessibilityValueAttribute,
   ];
   // TODO(tapted): Add additional attributes based on role.
 }
@@ -305,6 +272,58 @@ RoleMap BuildSubroleMap() {
   return nil;
 }
 
+// NSAccessibility attributes.
+
+// Helper function for string attributes that don't require extra processing.
+- (NSString*)retrieveAXStringAttribute:(ui::AXStringAttribute)attribute {

[tapted, 2016/05/30 11:30:21]

Since this essentially wraps node_->GetStringAttribute, let's call this
getStringAttribute. Then, since this forms part of the internal API, this should
be redeclared in a private category in this file.

before @implementation AXPlatformNodeCocoa above, do

@interface AXPlatformNodeCocoa ()
- (NSString*)getStringAttribute:(ui::AXStringAttribute)attribute;
@end

Then things declared in private categories, should be defined just after the
public categories (so move this up to come after boundsInScreen)

[Patti Lor, 2016/06/03 04:51:03]

Done.

+  std::string attributeValue;
+  if (node_->GetStringAttribute(attribute, &attributeValue))
+    return base::SysUTF8ToNSString(attributeValue);
+  return nil;
+}
+
+- (NSArray*)AXChildren {
+  if (!node_)
+    return nil;
+  int count = node_->GetChildCount();
+  NSMutableArray* children = [NSMutableArray arrayWithCapacity:count];
+  for (int i = 0; i < count; ++i)
+    [children addObject:node_->ChildAtIndex(i)];
+  return NSAccessibilityUnignoredChildren(children);
+}
+
+- (id)AXParent {
+  if (!node_)
+    return nil;
+  return NSAccessibilityUnignoredAncestor(node_->GetParent());
+}
+
+- (NSValue*)AXPosition {
+  return [NSValue valueWithPoint:self.boundsInScreen.origin];
+}
+
+- (NSString*)AXRole {
+  if (!node_)
+    return nil;
+  return [[self class] nativeRoleFromAXRole:node_->GetData().role];
+}
+
+- (NSValue*)AXSize {
+  return [NSValue valueWithSize:self.boundsInScreen.size];
+}
+
+- (NSString*)AXTitle {
+  return [self retrieveAXStringAttribute:ui::AX_ATTR_NAME];
+}
+
+- (NSString*)AXRoleDescription {
+  return [self retrieveAXStringAttribute:ui::AX_ATTR_DESCRIPTION];
+}
+
+- (NSString*)AXValue {
+  return [self retrieveAXStringAttribute:ui::AX_ATTR_VALUE];
+}
+
 @end
 
 namespace ui {