MacViews a11y: Support the "Show menu" action in Textfield and Combobox.

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 240240e6180bc11f40e56de4fa36fdafd9e65b81..2ae6c78132ee1ff34f62c2de0896c8775ba2f2ee 100644
--- a/ui/accessibility/platform/ax_platform_node_mac.mm
+++ b/ui/accessibility/platform/ax_platform_node_mac.mm
@@ -20,21 +20,15 @@
 
 namespace {
 
-struct RoleMapEntry {
-  ui::AXRole value;
-  NSString* nativeValue;
-};
+using RoleMap = std::map<ui::AXRole, NSString*>;
+using EventMap = std::map<ui::AXEvent, NSString*>;
+using ActionMap = std::map<ui::AXAction, NSString*>;
 
-struct EventMapEntry {
-  ui::AXEvent value;
-  NSString* nativeValue;
-};
-
-typedef std::map<ui::AXRole, NSString*> RoleMap;
-typedef std::map<ui::AXEvent, NSString*> EventMap;
+// The AXAction for NSAccessibilityPressAction, which needs special handling.
+constexpr ui::AXAction kActionForPress = ui::AX_ACTION_DO_DEFAULT;
 
 RoleMap BuildRoleMap() {
-  const RoleMapEntry roles[] = {
+  const RoleMap::value_type roles[] = {
       {ui::AX_ROLE_ABBR, NSAccessibilityGroupRole},
       {ui::AX_ROLE_ALERT, NSAccessibilityGroupRole},
       {ui::AX_ROLE_ALERT_DIALOG, NSAccessibilityGroupRole},
@@ -157,14 +151,11 @@ RoleMap BuildRoleMap() {
       // { ui::AX_ROLE_SCROLL_AREA, NSAccessibilityScrollAreaRole },
   };
 
-  RoleMap role_map;
-  for (size_t i = 0; i < arraysize(roles); ++i)
-    role_map[roles[i].value] = roles[i].nativeValue;
-  return role_map;
+  return RoleMap(begin(roles), end(roles));
 }
 
 RoleMap BuildSubroleMap() {
-  const RoleMapEntry subroles[] = {
+  const RoleMap::value_type subroles[] = {
       {ui::AX_ROLE_ALERT, @"AXApplicationAlert"},
       {ui::AX_ROLE_ALERT_DIALOG, @"AXApplicationAlertDialog"},
       {ui::AX_ROLE_APPLICATION, @"AXLandmarkApplication"},
@@ -198,14 +189,11 @@ RoleMap BuildSubroleMap() {
       {ui::AX_ROLE_TREE_ITEM, NSAccessibilityOutlineRowSubrole},
   };
 
-  RoleMap subrole_map;
-  for (size_t i = 0; i < arraysize(subroles); ++i)
-    subrole_map[subroles[i].value] = subroles[i].nativeValue;
-  return subrole_map;
+  return RoleMap(begin(subroles), end(subroles));
 }
 
 EventMap BuildEventMap() {
-  const EventMapEntry events[] = {
+  const EventMap::value_type events[] = {
       {ui::AX_EVENT_FOCUS, NSAccessibilityFocusedUIElementChangedNotification},
       {ui::AX_EVENT_TEXT_CHANGED, NSAccessibilityTitleChangedNotification},
       {ui::AX_EVENT_VALUE_CHANGED, NSAccessibilityValueChangedNotification},
@@ -214,10 +202,22 @@ EventMap BuildEventMap() {
       // TODO(patricialor): Add more events.
   };
 
-  EventMap event_map;
-  for (size_t i = 0; i < arraysize(events); ++i)
-    event_map[events[i].value] = events[i].nativeValue;
-  return event_map;
+  return EventMap(begin(events), end(events));
+}
+
+ActionMap BuildActionMap() {
+  const ActionMap::value_type entries[] = {
+      {ui::AX_ACTION_DECREMENT, NSAccessibilityDecrementAction},
+      {kActionForPress, NSAccessibilityPressAction},
+      {ui::AX_ACTION_INCREMENT, NSAccessibilityIncrementAction},
+      {ui::AX_ACTION_SHOW_CONTEXT_MENU, NSAccessibilityShowMenuAction},
+  };
+  return ActionMap(begin(entries), end(entries));
+}
+
+const ActionMap& GetActionMap() {
+  CR_DEFINE_STATIC_LOCAL(const ActionMap, action_map, (BuildActionMap()));
+  return action_map;
 }
 
 void NotifyMacEvent(AXPlatformNodeCocoa* target, ui::AXEvent event_type) {
@@ -240,24 +240,21 @@ void NotifyMacEvent(AXPlatformNodeCocoa* target, ui::AXEvent event_type) {
 
 @synthesize node = node_;
 
-// A mapping of AX roles to native roles.
 + (NSString*)nativeRoleFromAXRole:(ui::AXRole)role {
-  CR_DEFINE_STATIC_LOCAL(RoleMap, role_map, (BuildRoleMap()));
-  RoleMap::iterator it = role_map.find(role);
+  CR_DEFINE_STATIC_LOCAL(const RoleMap, role_map, (BuildRoleMap()));
+  RoleMap::const_iterator it = role_map.find(role);
   return it != role_map.end() ? it->second : NSAccessibilityUnknownRole;
 }
 
-// A mapping of AX roles to native subroles.
 + (NSString*)nativeSubroleFromAXRole:(ui::AXRole)role {
-  CR_DEFINE_STATIC_LOCAL(RoleMap, subrole_map, (BuildSubroleMap()));
-  RoleMap::iterator it = subrole_map.find(role);
+  CR_DEFINE_STATIC_LOCAL(const RoleMap, subrole_map, (BuildSubroleMap()));
+  RoleMap::const_iterator it = subrole_map.find(role);
   return it != subrole_map.end() ? it->second : nil;
 }
 
-// A mapping of AX events to native notifications.
 + (NSString*)nativeNotificationFromAXEvent:(ui::AXEvent)event {
-  CR_DEFINE_STATIC_LOCAL(EventMap, event_map, (BuildEventMap()));
-  EventMap::iterator it = event_map.find(event);
+  CR_DEFINE_STATIC_LOCAL(const EventMap, event_map, (BuildEventMap()));
+  EventMap::const_iterator it = event_map.find(event);
   return it != event_map.end() ? it->second : nil;
 }
 
@@ -323,18 +320,34 @@ void NotifyMacEvent(AXPlatformNodeCocoa* target, ui::AXEvent event_type) {
   base::scoped_nsobject<NSMutableArray> axActions(
       [[NSMutableArray alloc] init]);
 
+  const ui::AXNodeData& data = node_->GetData();
+
   // VoiceOver expects the "press" action to be first.
-  if (ui::IsRoleClickable(node_->GetData().role))
+  if (ui::IsRoleClickable(data.role) || data.HasAction(kActionForPress))
     [axActions addObject:NSAccessibilityPressAction];
 
+  for (const ActionMap::value_type& entry : GetActionMap()) {
+    if (entry.first == kActionForPress)
+      continue;
+
+    DCHECK(![entry.second isEqualToString:NSAccessibilityPressAction]);
+
+    if (data.HasAction(entry.first))
+      [axActions addObject:entry.second];
+  }
+
   return axActions.autorelease();
 }
 
 - (void)accessibilityPerformAction:(NSString*)action {
   DCHECK([[self accessibilityActionNames] containsObject:action]);
   ui::AXActionData data;
-  if ([action isEqualToString:NSAccessibilityPressAction])
-    data.action = ui::AX_ACTION_DO_DEFAULT;
+  for (const ActionMap::value_type& entry : GetActionMap()) {

[dmazzoni, 2017/06/21 06:09:35]

It doesn't look like you're ever using ActionMap as a map, i.e.
looking up a key and getting a value.

If you reversed it, you could look up the Mac action and retrieve
the Chrome action.

Alternatively, if you made it a vector of pairs, you could just enforce
that kActionForPress is first and not have to have any special cases
in accessibilityActionNames

[tapted, 2017/06/21 06:52:55]

Indeed! good catch. and it's as easy as changing the typedef (I had tried, but
was on the fence). I settled for a map in case we wanted a
+(NSString*)nativeActionFromAXAction:(ui::AXAction)action; to go with the others
in future. I had that on earlier CLs but I couldn't find a use for that now in
browser_accessibility_mac so deleted it. I'll put up a CL using vector, and with
the press action first.

[tapted, 2017/06/21 11:13:11]

Well.. everything _compiled_ fine with just the typedef change, but it needed a
bit more. Not as elegant as I was hoping - happy to try other things.

+    if ([action isEqualToString:entry.second]) {
+      data.action = entry.first;
+      break;
+    }
+  }
 
   // Note ui::AX_ACTIONs which are just overwriting an accessibility attribute
   // are already implemented in -accessibilitySetValue:forAttribute:, so ignore