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

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 <stddef.h>
 
 #include "base/macros.h"
 #include "base/strings/sys_string_conversions.h"
 #include "ui/accessibility/ax_action_data.h"
 #include "ui/accessibility/ax_node_data.h"
 #include "ui/accessibility/ax_role_properties.h"
 #include "ui/accessibility/platform/ax_platform_node.h"
 #include "ui/accessibility/platform/ax_platform_node_delegate.h"
 #include "ui/base/l10n/l10n_util.h"
 #import "ui/gfx/mac/coordinate_conversion.h"
 #include "ui/strings/grit/ui_strings.h"
 
 namespace {
 
-struct RoleMapEntry {
-  ui::AXRole value;
-  NSString* nativeValue;
-};
-
-struct EventMapEntry {
-  ui::AXEvent value;
-  NSString* nativeValue;
-};
-
-typedef std::map<ui::AXRole, NSString*> RoleMap;
-typedef std::map<ui::AXEvent, NSString*> EventMap;
+using RoleMap = std::map<ui::AXRole, NSString*>;
+using EventMap = std::map<ui::AXEvent, NSString*>;
+using ActionList = std::vector<std::pair<ui::AXAction, NSString*>>;
 
 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},
       {ui::AX_ROLE_ANCHOR, NSAccessibilityGroupRole},
       {ui::AX_ROLE_ANNOTATION, NSAccessibilityUnknownRole},
       {ui::AX_ROLE_APPLICATION, NSAccessibilityGroupRole},
       {ui::AX_ROLE_ARTICLE, NSAccessibilityGroupRole},
       {ui::AX_ROLE_AUDIO, NSAccessibilityGroupRole},
       {ui::AX_ROLE_BANNER, NSAccessibilityGroupRole},
       {ui::AX_ROLE_BLOCKQUOTE, NSAccessibilityGroupRole},
@@ skipping 102 matching lines @@
       {ui::AX_ROLE_TREE_ITEM, NSAccessibilityRowRole},
       {ui::AX_ROLE_VIDEO, NSAccessibilityGroupRole},
       {ui::AX_ROLE_WEB_AREA, @"AXWebArea"},
       {ui::AX_ROLE_WINDOW, NSAccessibilityWindowRole},
 
       // TODO(dtseng): we don't correctly support the attributes for these
       // roles.
       // { 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"},
       {ui::AX_ROLE_ARTICLE, @"AXDocumentArticle"},
       {ui::AX_ROLE_BANNER, @"AXLandmarkBanner"},
       {ui::AX_ROLE_COMPLEMENTARY, @"AXLandmarkComplementary"},
       {ui::AX_ROLE_CONTENT_INFO, @"AXLandmarkContentInfo"},
       {ui::AX_ROLE_DEFINITION, @"AXDefinition"},
       {ui::AX_ROLE_DESCRIPTION_LIST_DETAIL, @"AXDefinition"},
       {ui::AX_ROLE_DESCRIPTION_LIST_TERM, @"AXTerm"},
@@ skipping 13 matching lines @@
       {ui::AX_ROLE_STATUS, @"AXApplicationStatus"},
       {ui::AX_ROLE_SWITCH, @"AXSwitch"},
       {ui::AX_ROLE_TAB_PANEL, @"AXTabPanel"},
       {ui::AX_ROLE_TERM, @"AXTerm"},
       {ui::AX_ROLE_TIMER, @"AXApplicationTimer"},
       {ui::AX_ROLE_TOGGLE_BUTTON, @"AXToggleButton"},
       {ui::AX_ROLE_TOOLTIP, @"AXUserInterfaceTooltip"},
       {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},
       {ui::AX_EVENT_TEXT_SELECTION_CHANGED,
        NSAccessibilitySelectedTextChangedNotification},
       // 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));
+}
+
+ActionList BuildActionList() {
+  const ActionList::value_type entries[] = {
+      // NSAccessibilityPressAction must come first in this list.
+      {ui::AX_ACTION_DO_DEFAULT, NSAccessibilityPressAction},
+
+      {ui::AX_ACTION_DECREMENT, NSAccessibilityDecrementAction},
+      {ui::AX_ACTION_INCREMENT, NSAccessibilityIncrementAction},
+      {ui::AX_ACTION_SHOW_CONTEXT_MENU, NSAccessibilityShowMenuAction},
+  };
+  return ActionList(begin(entries), end(entries));
+}
+
+const ActionList& GetActionList() {
+  CR_DEFINE_STATIC_LOCAL(const ActionList, action_map, (BuildActionList()));
+  return action_map;
 }
 
 void NotifyMacEvent(AXPlatformNodeCocoa* target, ui::AXEvent event_type) {
   NSAccessibilityPostNotification(
       target, [AXPlatformNodeCocoa nativeNotificationFromAXEvent:event_type]);
 }
 
+// Returns true if |action| should be added implicitly for |data|.
+bool HasImplicitAction(const ui::AXNodeData& data, ui::AXAction action) {
+  return action == ui::AX_ACTION_DO_DEFAULT && ui::IsRoleClickable(data.role);
+}
+
+// For roles that show a menu for the default action, ensure "show menu" also
+// appears in available actions, but only if that's not already used for a
+// context menu. It will be mapped back to the default action when performed.
+bool AlsoUseShowMenuActionForDefaultAction(const ui::AXNodeData& data) {
+  return HasImplicitAction(data, ui::AX_ACTION_DO_DEFAULT) &&
+         !data.HasAction(ui::AX_ACTION_SHOW_CONTEXT_MENU) &&
+         data.role == ui::AX_ROLE_POP_UP_BUTTON;
+}
+
 }  // namespace
 
 @interface AXPlatformNodeCocoa ()
 // Helper function for string attributes that don't require extra processing.
 - (NSString*)getStringAttribute:(ui::AXStringAttribute)attribute;
 // Returns AXValue, or nil if AXValue isn't an NSString.
 - (NSString*)getAXValueAsString;
 @end
 
 @implementation AXPlatformNodeCocoa {
   ui::AXPlatformNodeBase* node_;  // Weak. Retains us.
 }
 
 @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;
 }
 
 - (instancetype)initWithNode:(ui::AXPlatformNodeBase*)node {
   if ((self = [super init])) {
     node_ = node;
   }
   return self;
 }
 
@@ skipping 45 matching lines @@
 }
 
 - (id)accessibilityFocusedUIElement {
   return node_->GetDelegate()->GetFocus();
 }
 
 - (NSArray*)accessibilityActionNames {
   base::scoped_nsobject<NSMutableArray> axActions(
       [[NSMutableArray alloc] init]);
 
-  // VoiceOver expects the "press" action to be first.
-  if (ui::IsRoleClickable(node_->GetData().role))
-    [axActions addObject:NSAccessibilityPressAction];
+  const ui::AXNodeData& data = node_->GetData();
+  const ActionList& action_list = GetActionList();
+
+  // VoiceOver expects the "press" action to be first. Note that some roles
+  // should be given a press action implicitly.
+  DCHECK([action_list[0].second isEqualToString:NSAccessibilityPressAction]);
+  for (const auto item : action_list) {
+    if (data.HasAction(item.first) || HasImplicitAction(data, item.first))
+      [axActions addObject:item.second];
+  }
+
+  if (AlsoUseShowMenuActionForDefaultAction(data))
+    [axActions addObject:NSAccessibilityShowMenuAction];
 
   return axActions.autorelease();
 }
 
 - (void)accessibilityPerformAction:(NSString*)action {
   DCHECK([[self accessibilityActionNames] containsObject:action]);
   ui::AXActionData data;
-  if ([action isEqualToString:NSAccessibilityPressAction])
+  if ([action isEqualToString:NSAccessibilityShowMenuAction] &&
+      AlsoUseShowMenuActionForDefaultAction(node_->GetData())) {
     data.action = ui::AX_ACTION_DO_DEFAULT;
+  } else {
+    for (const ActionList::value_type& entry : GetActionList()) {
+      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
   // those here.
 
   if (data.action != ui::AX_ACTION_NONE)
     node_->GetDelegate()->AccessibilityPerformAction(data);
 }
 
 - (NSArray*)accessibilityAttributeNames {
@@ skipping 436 matching lines @@
   }
   NotifyMacEvent(native_node_, event_type);
 }
 
 int AXPlatformNodeMac::GetIndexInParent() {
   // TODO(dmazzoni): implement this.  http://crbug.com/396137
   return -1;
 }
 
 }  // namespace ui