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..5be1e660a87e2119e4164e61460f0a2d1ab53a60 100644
--- a/ui/accessibility/platform/ax_platform_node_mac.mm
+++ b/ui/accessibility/platform/ax_platform_node_mac.mm
@@ -10,6 +10,7 @@
 #include "base/macros.h"
 #include "base/strings/sys_string_conversions.h"
 #import "ui/accessibility/ax_node_data.h"
+#include "ui/accessibility/ax_view_state.h"
 #import "ui/accessibility/platform/ax_platform_node_delegate.h"
 #import "ui/gfx/mac/coordinate_conversion.h"
 
@@ -190,6 +191,11 @@ RoleMap BuildSubroleMap() {
 
 }  // namespace
 
+@interface AXPlatformNodeCocoa ()
+// Helper function for string attributes that don't require extra processing.
+- (NSString*)getStringAttribute:(ui::AXStringAttribute)attribute;
+@end
+
 @implementation AXPlatformNodeCocoa
 
 // A mapping of AX roles to native roles.
@@ -223,6 +229,83 @@ RoleMap BuildSubroleMap() {
   return gfx::ScreenRectToNSRect(node_->GetBoundsInScreen());
 }
 
+- (NSString*)getStringAttribute:(ui::AXStringAttribute)attribute {
+  std::string attributeValue;
+  if (node_->GetStringAttribute(attribute, &attributeValue))
+    return base::SysUTF8ToNSString(attributeValue);
+  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 {
+  // These attributes are required on all accessibility objects.
+  NSMutableArray* axAttributes = [NSMutableArray

[tapted, 2016/06/10 03:17:17]

we should keep the array literals as constants. E.g.

NSArray* const kAllRoleAttributes[] = @[
  ...
];

NSArray* const kValueAttributes[] = @[
  ...
];


Then just start with

scoped_nsobject<NSMutableArray> axAttributes([[NSMutableArray alloc] init]);

[axAttributes addObjectsFromArray:...
swtich(..) {
[axAttributes addObjectsFromArray:...
}

return axAttributes.autorelease();

[Patti Lor, 2016/06/16 07:05:21]

Done. Thanks for the const tip, I hadn't known about that!

+      arrayWithObjects:NSAccessibilityChildrenAttribute,
+                       NSAccessibilityParentAttribute,
+                       NSAccessibilityPositionAttribute,
+                       NSAccessibilityRoleAttribute,
+                       NSAccessibilitySizeAttribute,
+                       NSAccessibilitySubroleAttribute,
+
+                       // 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, nil];
+  switch (node_->GetData().role) {
+    case ui::AX_ROLE_CHECK_BOX:
+    case ui::AX_ROLE_COMBO_BOX:
+    case ui::AX_ROLE_MENU_ITEM_CHECK_BOX:
+    case ui::AX_ROLE_MENU_ITEM_RADIO:
+    case ui::AX_ROLE_RADIO_BUTTON:
+    case ui::AX_ROLE_SEARCH_BOX:
+    case ui::AX_ROLE_SLIDER:
+    case ui::AX_ROLE_SLIDER_THUMB:
+    case ui::AX_ROLE_TOGGLE_BUTTON:
+    case ui::AX_ROLE_TEXT_FIELD:
+      [axAttributes addObjectsFromArray:@[ NSAccessibilityValueAttribute ]];
+      break;
+    // TODO(tapted): Add additional attributes based on role.
+    default:
+      break;
+  }
+  return axAttributes;
+}
+
+- (BOOL)accessibilityIsAttributeSettable:(NSString*)attribute {
+  return NO;
+}
+
+- (id)accessibilityAttributeValue:(NSString*)attribute {
+  SEL selector = NSSelectorFromString(attribute);
+  if ([self respondsToSelector:selector])
+    return [self performSelector:selector];
+  return nil;
+}
+
+// NSAccessibility attributes.
+
 - (NSArray*)AXChildren {
   if (!node_)
     return nil;
@@ -253,56 +336,34 @@ RoleMap BuildSubroleMap() {
   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];
+- (NSString*)AXSubrole {
+  ui::AXRole role = node_->GetData().role;
+  switch (role) {
+    case ui::AX_ROLE_TEXT_FIELD: {
+      if (ui::AXViewState::HasStateFlag(node_->GetData().state,
+                                        ui::AX_STATE_PROTECTED)) {
+        return NSAccessibilitySecureTextFieldSubrole;
+      }
+    } break;

[tapted, 2016/06/10 03:17:17]

break would go inside the curlies, but I don't think we need curlies --
typically they're just needed when declaring variables inside a `case`

[Patti Lor, 2016/06/16 07:05:21]

Done.

+    default:
+      break;
   }
-  return NSAccessibilityUnignoredAncestor(self);
+  return [AXPlatformNodeCocoa nativeSubroleFromAXRole:role];
 }
 
-- (NSArray*)accessibilityActionNames {
-  return nil;
-}
-
-- (NSArray*)accessibilityAttributeNames {
-  // These attributes are required on all accessibility objects.
-  return @[
-    NSAccessibilityChildrenAttribute,
-    NSAccessibilityParentAttribute,
-    NSAccessibilityPositionAttribute,
-    NSAccessibilityRoleAttribute,
-    NSAccessibilitySizeAttribute,
-
-    // 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,
-  ];
-  // TODO(tapted): Add additional attributes based on role.
+- (NSString*)AXTitle {
+  return [self getStringAttribute:ui::AX_ATTR_NAME];
 }
 
-- (BOOL)accessibilityIsAttributeSettable:(NSString*)attribute {
-  return NO;
+- (NSString*)AXRoleDescription {
+  NSString* description = [self getStringAttribute:ui::AX_ATTR_DESCRIPTION];
+  if (!description)
+    return NSAccessibilityRoleDescription([self AXRole], [self AXSubrole]);
+  return description;
 }
 
-- (id)accessibilityAttributeValue:(NSString*)attribute {
-  SEL selector = NSSelectorFromString(attribute);
-  if ([self respondsToSelector:selector])
-    return [self performSelector:selector];
-  return nil;
+- (NSString*)AXValue {
+  return [self getStringAttribute:ui::AX_ATTR_VALUE];
 }
 
 @end