Expose an accessible relation between the main window and active alert.

ui/views/accessibility/native_view_accessibility_win.h

 // Copyright (c) 2012 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.
 
 #ifndef UI_VIEWS_ACCESSIBILITY_NATIVE_VIEW_ACCESSIBILITY_WIN_H_
 #define UI_VIEWS_ACCESSIBILITY_NATIVE_VIEW_ACCESSIBILITY_WIN_H_
 
 #include <atlbase.h>
 #include <atlcom.h>
 #include <oleacc.h>
 
 #include <UIAutomationCore.h>
 
 #include <set>
+#include <vector>
 
 #include "third_party/iaccessible2/ia2_api_all.h"
 #include "ui/accessibility/ax_view_state.h"
 #include "ui/views/accessibility/native_view_accessibility.h"
 #include "ui/views/controls/native/native_view_host.h"
 #include "ui/views/view.h"
 
 namespace ui {
 enum TextBoundaryDirection;
 enum TextBoundaryType;
 }
 
 namespace views {
 
 ////////////////////////////////////////////////////////////////////////////////
 //
 // NativeViewAccessibilityWin
 //
 // Class implementing the MSAA IAccessible COM interface for a generic View,
 // providing accessibility to be used by screen readers and other assistive
 // technology (AT).
 //
 ////////////////////////////////////////////////////////////////////////////////
 class __declspec(uuid("26f5641a-246d-457b-a96d-07f3fae6acf2"))
 NativeViewAccessibilityWin
   : public CComObjectRootEx<CComMultiThreadModel>,
-    public IDispatchImpl<IAccessible2, &IID_IAccessible2,
+    public IDispatchImpl<IAccessible2_2, &IID_IAccessible2_2,

[aboxhall, 2014/05/07 15:26:30]

Why all the _2s?

[dmazzoni, 2014/05/07 17:36:37]

Believe it or not, that's what they call the extension to the latest extension
to the IAccessible2 type in the iaccessible2 umbrella spec - it's
IAccessible2_2. We also now have IAccessibleTable2, IAccessibleText2, and so on.
Pretty ugly!

Basically they can't add new interfaces to an existing abstract class in each
new spec version without breaking old code, so they have to subclass it with a
new abstract class each time.

http://accessibility.linuxfoundation.org/a11yspecs/ia2/docs/html/

                            &LIBID_IAccessible2Lib>,
     public IAccessibleText,
     public IServiceProvider,
     public IAccessibleEx,
     public IRawElementProviderSimple,
     public NativeViewAccessibility {
  public:
   BEGIN_COM_MAP(NativeViewAccessibilityWin)
-    COM_INTERFACE_ENTRY2(IDispatch, IAccessible2)
-    COM_INTERFACE_ENTRY2(IAccessible, IAccessible2)
-    COM_INTERFACE_ENTRY(IAccessible2)
+    COM_INTERFACE_ENTRY2(IDispatch, IAccessible2_2)
+    COM_INTERFACE_ENTRY2(IAccessible, IAccessible2_2)
+    COM_INTERFACE_ENTRY(IAccessible2_2)
     COM_INTERFACE_ENTRY(IAccessibleText)
     COM_INTERFACE_ENTRY(IServiceProvider)
     COM_INTERFACE_ENTRY(IAccessibleEx)
     COM_INTERFACE_ENTRY(IRawElementProviderSimple)
   END_COM_MAP()
 
   virtual ~NativeViewAccessibilityWin();
 
   // NativeViewAccessibility.
   virtual void NotifyAccessibilityEvent(
@@ skipping 75 matching lines @@
   //
 
   STDMETHODIMP role(LONG* role);
 
   STDMETHODIMP get_states(AccessibleStates* states);
 
   STDMETHODIMP get_uniqueID(LONG* unique_id);
 
   STDMETHODIMP get_windowHandle(HWND* window_handle);
 
+  STDMETHODIMP get_relationTargetsOfType(BSTR type,
+                                         long max_targets,
+                                         IUnknown ***targets,
+                                         long *n_targets);
+
   //
   // IAccessible2 methods not implemented.
   //
 
   STDMETHODIMP get_attributes(BSTR* attributes) {
     return E_NOTIMPL;
   }
+  STDMETHODIMP get_attribute(BSTR name, VARIANT* attribute) {
+    return E_NOTIMPL;
+  }
   STDMETHODIMP get_indexInParent(LONG* index_in_parent) {
     return E_NOTIMPL;
   }
   STDMETHODIMP get_extendedRole(BSTR* extended_role) {
     return E_NOTIMPL;
   }
   STDMETHODIMP get_nRelations(LONG* n_relations) {
     return E_NOTIMPL;
   }
   STDMETHODIMP get_relation(LONG relation_index,
@@ skipping 33 matching lines @@
   }
   STDMETHODIMP get_localizedExtendedStates(
       LONG max_localized_extended_states,
       BSTR** localized_extended_states,
       LONG* n_localized_extended_states) {
     return E_NOTIMPL;
   }
   STDMETHODIMP get_locale(IA2Locale* locale) {
     return E_NOTIMPL;
   }
+  STDMETHODIMP get_accessibleWithCaret(IUnknown** accessible,
+                                       long* caret_offset) {
+    return E_NOTIMPL;
+  }
 
   //
   // IAccessibleText methods.
   //
 
   STDMETHODIMP get_nCharacters(LONG* n_characters);
 
   STDMETHODIMP get_caretOffset(LONG* offset);
 
   STDMETHODIMP get_nSelections(LONG* n_selections);
@@ skipping 171 matching lines @@
   LONG FindBoundary(const base::string16& text,
                     IA2TextBoundaryType ia2_boundary,
                     LONG start_offset,
                     ui::TextBoundaryDirection direction);
 
   // Populates the given vector with all widgets that are either a child
   // or are owned by this view's widget, and who are not contained in a
   // NativeViewHost.
   void PopulateChildWidgetVector(std::vector<Widget*>* child_widgets);
 
+  // Adds this view to alert_target_view_storage_ids_.
+  void AddAlertTarget();
+
+  // Remove this view from alert_target_view_storage_ids_.

[aboxhall, 2014/05/07 15:26:30]

Nit: Removes

[dmazzoni, 2014/05/07 17:36:37]

Done.

+  void RemoveAlertTarget();
+
   // Give CComObject access to the class constructor.
   template <class Base> friend class CComObject;
 
   // Member View needed for view-specific calls.
   View* view_;
 
   // A unique id for each object, needed for IAccessible2.
   long unique_id_;
 
   // Next unique id to assign.
   static long next_unique_id_;
 
   // Circular queue size.
   static const int kMaxViewStorageIds = 20;
 
   // Circular queue of view storage ids corresponding to child ids
   // used to post notifications using NotifyWinEvent.
   static int view_storage_ids_[kMaxViewStorageIds];
 
   // Next index into |view_storage_ids_| to use.
   static int next_view_storage_id_index_;
 
+  // A vector of view storage ids of views that have been the target of
+  // an alert event, in order to provide an api to quickly identify all
+  // open alerts.
+  static std::vector<int> alert_target_view_storage_ids_;
+
   DISALLOW_COPY_AND_ASSIGN(NativeViewAccessibilityWin);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_ACCESSIBILITY_NATIVE_VIEW_ACCESSIBILITY_WIN_H_