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

This will specifically allow screen readers to query the accessible
object for the main window and quickly get a list of an alerts that
are visible - for example infobars, bubbles, and the Chrome menu itself
if it has an alert icon in it.

BUG=369903

Review URL: https://codereview.chromium.org/266963002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@270074 0039d316-1c4b-4281-b951-d872f2087c98

ui/views/accessibility/native_view_accessibility_win.cc

@@ -189,6 +189,7 @@ void AccessibleWebViewRegistry::QueryIAccessible2Interface(View* web_view) {
 long NativeViewAccessibilityWin::next_unique_id_ = 1;
 int NativeViewAccessibilityWin::view_storage_ids_[kMaxViewStorageIds] = {0};
 int NativeViewAccessibilityWin::next_view_storage_id_index_ = 0;
+std::vector<int> NativeViewAccessibilityWin::alert_target_view_storage_ids_;
 
 // static
 NativeViewAccessibility* NativeViewAccessibility::Create(View* view) {
@@ -210,6 +211,7 @@ NativeViewAccessibilityWin::NativeViewAccessibilityWin()
 }
 
 NativeViewAccessibilityWin::~NativeViewAccessibilityWin() {
+  RemoveAlertTarget();
 }
 
 void NativeViewAccessibilityWin::NotifyAccessibilityEvent(
@@ -236,6 +238,10 @@ void NativeViewAccessibilityWin::NotifyAccessibilityEvent(
   ::NotifyWinEvent(MSAAEvent(event_type), hwnd, OBJID_CLIENT, child_id);
   next_view_storage_id_index_ =
       (next_view_storage_id_index_ + 1) % kMaxViewStorageIds;
+
+  // Keep track of views that are a target of an alert event.
+  if (event_type == ui::AX_EVENT_ALERT)
+    AddAlertTarget();
 }
 
 gfx::NativeViewAccessible NativeViewAccessibilityWin::GetNativeObject() {
@@ -865,6 +871,59 @@ STDMETHODIMP NativeViewAccessibilityWin::get_windowHandle(HWND* window_handle) {
   return *window_handle ? S_OK : S_FALSE;
 }
 
+STDMETHODIMP NativeViewAccessibilityWin::get_relationTargetsOfType(
+    BSTR type_bstr,
+    long max_targets,
+    IUnknown ***targets,
+    long *n_targets) {
+  if (!view_)
+    return E_FAIL;
+
+  if (!targets || !n_targets)
+    return E_INVALIDARG;
+
+  *n_targets = 0;
+  *targets = NULL;
+
+  // Only respond to requests for relations of type "alerts" on the
+  // root view.
+  base::string16 type(type_bstr);
+  if (type != L"alerts" || view_->parent())
+    return S_FALSE;
+
+  // Collect all of the alert views that are still valid.
+  std::vector<View*> alert_views;
+  ViewStorage* view_storage = ViewStorage::GetInstance();
+  for (size_t i = 0; i < alert_target_view_storage_ids_.size(); ++i) {
+    int view_storage_id = alert_target_view_storage_ids_[i];
+    View* view = view_storage->RetrieveView(view_storage_id);
+    if (!view || !view_->Contains(view))
+      continue;
+    alert_views.push_back(view);
+  }
+
+  long count = alert_views.size();
+  if (count == 0)
+    return S_FALSE;
+
+  // Don't return more targets than max_targets - but note that the caller
+  // is allowed to specify max_targets=0 to mean no limit.
+  if (max_targets > 0 && count > max_targets)
+    count = max_targets;
+
+  // Return the number of targets.
+  *n_targets = count;
+
+  // Allocate COM memory for the result array and populate it.
+  *targets = static_cast<IUnknown**>(
+      CoTaskMemAlloc(count * sizeof(IUnknown*)));
+  for (long i = 0; i < count; ++i) {
+    (*targets)[i] = alert_views[i]->GetNativeViewAccessible();
+    (*targets)[i]->AddRef();
+  }
+  return S_OK;
+}
+
 //
 // IAccessibleText
 //
@@ -1071,11 +1130,12 @@ STDMETHODIMP NativeViewAccessibilityWin::QueryService(
   if (!view_)
     return E_FAIL;
 
-  if (riid == IID_IAccessible2)
+  if (riid == IID_IAccessible2 || riid == IID_IAccessible2_2)
     AccessibleWebViewRegistry::GetInstance()->EnableIAccessible2Support();
 
   if (guidService == IID_IAccessible ||
       guidService == IID_IAccessible2 ||
+      guidService == IID_IAccessible2_2 ||
       guidService == IID_IAccessibleText)  {
     return QueryInterface(riid, object);
   }
@@ -1412,4 +1472,32 @@ void NativeViewAccessibilityWin::PopulateChildWidgetVector(
   }
 }
 
+void NativeViewAccessibilityWin::AddAlertTarget() {
+  ViewStorage* view_storage = ViewStorage::GetInstance();
+  for (size_t i = 0; i < alert_target_view_storage_ids_.size(); ++i) {
+    int view_storage_id = alert_target_view_storage_ids_[i];
+    View* view = view_storage->RetrieveView(view_storage_id);
+    if (view == view_)
+      return;
+  }
+  int view_storage_id = view_storage->CreateStorageID();
+  view_storage->StoreView(view_storage_id, view_);
+  alert_target_view_storage_ids_.push_back(view_storage_id);
+}
+
+void NativeViewAccessibilityWin::RemoveAlertTarget() {
+  ViewStorage* view_storage = ViewStorage::GetInstance();
+  size_t i = 0;
+  while (i < alert_target_view_storage_ids_.size()) {
+    int view_storage_id = alert_target_view_storage_ids_[i];
+    View* view = view_storage->RetrieveView(view_storage_id);
+    if (view == NULL || view == view_) {
+      alert_target_view_storage_ids_.erase(
+          alert_target_view_storage_ids_.begin() + i);
+    } else {
+      ++i;
+    }
+  }
+}
+
 }  // namespace views

ui/views/accessibility/native_view_accessibility_win.h

@@ -12,6 +12,7 @@
 #include <UIAutomationCore.h>
 
 #include <set>
+#include <vector>
 
 #include "third_party/iaccessible2/ia2_api_all.h"
 #include "ui/accessibility/ax_view_state.h"
@@ -38,7 +39,7 @@ namespace views {
 class __declspec(uuid("26f5641a-246d-457b-a96d-07f3fae6acf2"))
 NativeViewAccessibilityWin
   : public CComObjectRootEx<CComMultiThreadModel>,
-    public IDispatchImpl<IAccessible2, &IID_IAccessible2,
+    public IDispatchImpl<IAccessible2_2, &IID_IAccessible2_2,
                            &LIBID_IAccessible2Lib>,
     public IAccessibleText,
     public IServiceProvider,
@@ -47,9 +48,9 @@ NativeViewAccessibilityWin
     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)
@@ -145,6 +146,11 @@ NativeViewAccessibilityWin
 
   STDMETHODIMP get_windowHandle(HWND* window_handle);
 
+  STDMETHODIMP get_relationTargetsOfType(BSTR type,
+                                         long max_targets,
+                                         IUnknown ***targets,
+                                         long *n_targets);
+
   //
   // IAccessible2 methods not implemented.
   //
@@ -152,6 +158,9 @@ NativeViewAccessibilityWin
   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;
   }
@@ -205,6 +214,10 @@ NativeViewAccessibilityWin
   STDMETHODIMP get_locale(IA2Locale* locale) {
     return E_NOTIMPL;
   }
+  STDMETHODIMP get_accessibleWithCaret(IUnknown** accessible,
+                                       long* caret_offset) {
+    return E_NOTIMPL;
+  }
 
   //
   // IAccessibleText methods.
@@ -396,6 +409,12 @@ NativeViewAccessibilityWin
   // NativeViewHost.
   void PopulateChildWidgetVector(std::vector<Widget*>* child_widgets);
 
+  // Adds this view to alert_target_view_storage_ids_.
+  void AddAlertTarget();
+
+  // Removes this view from alert_target_view_storage_ids_.
+  void RemoveAlertTarget();
+
   // Give CComObject access to the class constructor.
   template <class Base> friend class CComObject;
 
@@ -418,6 +437,11 @@ NativeViewAccessibilityWin
   // 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);
 };
 

ui/views/accessibility/native_view_accessibility_win_unittest.cc

@@ -7,14 +7,33 @@
 #include "base/win/scoped_bstr.h"
 #include "base/win/scoped_comptr.h"
 #include "base/win/scoped_variant.h"
+#include "third_party/iaccessible2/ia2_api_all.h"
 #include "ui/views/accessibility/native_view_accessibility.h"
 #include "ui/views/controls/textfield/textfield.h"
 #include "ui/views/test/views_test_base.h"
 
+using base::win::ScopedBstr;
+using base::win::ScopedComPtr;
+using base::win::ScopedVariant;
+
 namespace views {
 namespace test {
 
-typedef ViewsTestBase NativeViewAcccessibilityWinTest;
+class NativeViewAcccessibilityWinTest : public ViewsTestBase {
+ public:
+  NativeViewAcccessibilityWinTest() {}
+  virtual ~NativeViewAcccessibilityWinTest() {}
+
+ protected:
+  void GetIAccessible2InterfaceForView(View* view, IAccessible2_2** result) {
+    ScopedComPtr<IAccessible> view_accessible(
+        view->GetNativeViewAccessible());
+    ScopedComPtr<IServiceProvider> service_provider;
+    ASSERT_EQ(S_OK, view_accessible.QueryInterface(service_provider.Receive()));
+    ASSERT_EQ(S_OK,
+        service_provider->QueryService(IID_IAccessible2_2, result));
+  }
+};
 
 TEST_F(NativeViewAcccessibilityWinTest, TextfieldAccessibility) {
   Widget widget;
@@ -31,32 +50,32 @@ TEST_F(NativeViewAcccessibilityWinTest, TextfieldAccessibility) {
   textfield->SetText(L"Value");
   content->AddChildView(textfield);
 
-  base::win::ScopedComPtr<IAccessible> content_accessible(
+  ScopedComPtr<IAccessible> content_accessible(
       content->GetNativeViewAccessible());
   LONG child_count = 0;
   ASSERT_EQ(S_OK, content_accessible->get_accChildCount(&child_count));
   ASSERT_EQ(1L, child_count);
 
-  base::win::ScopedComPtr<IDispatch> textfield_dispatch;
-  base::win::ScopedComPtr<IAccessible> textfield_accessible;
-  base::win::ScopedVariant child_index(1);
+  ScopedComPtr<IDispatch> textfield_dispatch;
+  ScopedComPtr<IAccessible> textfield_accessible;
+  ScopedVariant child_index(1);
   ASSERT_EQ(S_OK, content_accessible->get_accChild(
       child_index, textfield_dispatch.Receive()));
   ASSERT_EQ(S_OK, textfield_dispatch.QueryInterface(
       textfield_accessible.Receive()));
 
-  base::win::ScopedBstr name;
-  base::win::ScopedVariant childid_self(CHILDID_SELF);
+  ScopedBstr name;
+  ScopedVariant childid_self(CHILDID_SELF);
   ASSERT_EQ(S_OK, textfield_accessible->get_accName(
       childid_self, name.Receive()));
   ASSERT_STREQ(L"Name", name);
 
-  base::win::ScopedBstr value;
+  ScopedBstr value;
   ASSERT_EQ(S_OK, textfield_accessible->get_accValue(
       childid_self, value.Receive()));
   ASSERT_STREQ(L"Value", value);
 
-  base::win::ScopedBstr new_value(L"New value");
+  ScopedBstr new_value(L"New value");
   ASSERT_EQ(S_OK, textfield_accessible->put_accValue(childid_self, new_value));
 
   ASSERT_STREQ(L"New value", textfield->text().c_str());
@@ -81,10 +100,10 @@ TEST_F(NativeViewAcccessibilityWinTest, UnattachedWebView) {
   content->AddChildView(web_view);
   NativeViewAccessibility::RegisterWebView(web_view);
 
-  base::win::ScopedComPtr<IAccessible> web_view_accessible(
+  ScopedComPtr<IAccessible> web_view_accessible(
       web_view->GetNativeViewAccessible());
-  base::win::ScopedComPtr<IDispatch> result_dispatch;
-  base::win::ScopedVariant child_index(-999);
+  ScopedComPtr<IDispatch> result_dispatch;
+  ScopedVariant child_index(-999);
   ASSERT_EQ(E_FAIL, web_view_accessible->get_accChild(
       child_index, result_dispatch.Receive()));
 
@@ -98,7 +117,7 @@ TEST_F(NativeViewAcccessibilityWinTest, AuraOwnedWidgets) {
   init_params.ownership = Widget::InitParams::WIDGET_OWNS_NATIVE_WIDGET;
   widget.Init(init_params);
 
-  base::win::ScopedComPtr<IAccessible> root_view_accessible(
+  ScopedComPtr<IAccessible> root_view_accessible(
       widget.GetRootView()->GetNativeViewAccessible());
 
   LONG child_count = 0;
@@ -118,5 +137,69 @@ TEST_F(NativeViewAcccessibilityWinTest, AuraOwnedWidgets) {
   ASSERT_EQ(2L, child_count);
 }
 
+TEST_F(NativeViewAcccessibilityWinTest, RetrieveAllAlerts) {
+  Widget widget;
+  Widget::InitParams init_params =
+      CreateParams(Widget::InitParams::TYPE_POPUP);
+  init_params.ownership = Widget::InitParams::WIDGET_OWNS_NATIVE_WIDGET;
+  widget.Init(init_params);
+
+  View* content = new View;
+  widget.SetContentsView(content);
+
+  View* infobar = new View;
+  content->AddChildView(infobar);
+
+  View* infobar2 = new View;
+  content->AddChildView(infobar2);
+
+  View* root_view = content->parent();
+  ASSERT_EQ(NULL, root_view->parent());
+
+  ScopedComPtr<IAccessible2_2> root_view_accessible;
+  GetIAccessible2InterfaceForView(root_view, root_view_accessible.Receive());
+
+  ScopedComPtr<IAccessible2_2> infobar_accessible;
+  GetIAccessible2InterfaceForView(infobar, infobar_accessible.Receive());
+
+  ScopedComPtr<IAccessible2_2> infobar2_accessible;
+  GetIAccessible2InterfaceForView(infobar2, infobar2_accessible.Receive());
+
+  // Initially, there are no alerts
+  ScopedBstr alerts_bstr(L"alerts");
+  IUnknown** targets;
+  long n_targets;
+  ASSERT_EQ(S_FALSE, root_view_accessible->get_relationTargetsOfType(
+      alerts_bstr, 0, &targets, &n_targets));
+  ASSERT_EQ(0, n_targets);
+
+  // Fire alert events on the infobars.
+  infobar->NotifyAccessibilityEvent(ui::AX_EVENT_ALERT, true);
+  infobar2->NotifyAccessibilityEvent(ui::AX_EVENT_ALERT, true);
+
+  // Now calling get_relationTargetsOfType should retrieve the alerts.
+  ASSERT_EQ(S_OK, root_view_accessible->get_relationTargetsOfType(
+      alerts_bstr, 0, &targets, &n_targets));
+  ASSERT_EQ(2, n_targets);
+  ASSERT_TRUE(infobar_accessible.IsSameObject(targets[0]));
+  ASSERT_TRUE(infobar2_accessible.IsSameObject(targets[1]));
+  CoTaskMemFree(targets);
+
+  // If we set max_targets to 1, we should only get the first one.
+  ASSERT_EQ(S_OK, root_view_accessible->get_relationTargetsOfType(
+      alerts_bstr, 1, &targets, &n_targets));
+  ASSERT_EQ(1, n_targets);
+  ASSERT_TRUE(infobar_accessible.IsSameObject(targets[0]));
+  CoTaskMemFree(targets);
+
+  // If we delete the first view, we should only get the second one now.
+  delete infobar;
+  ASSERT_EQ(S_OK, root_view_accessible->get_relationTargetsOfType(
+      alerts_bstr, 0, &targets, &n_targets));
+  ASSERT_EQ(1, n_targets);
+  ASSERT_TRUE(infobar2_accessible.IsSameObject(targets[0]));
+  CoTaskMemFree(targets);
+}
+
 }  // namespace test
 }  // namespace views

ui/views/views.gyp

@@ -683,6 +683,9 @@
           ],
         }],
         ['OS=="win"', {
+          'dependencies': [
+            '../../third_party/iaccessible2/iaccessible2.gyp:iaccessible2',
+          ],
           'link_settings': {
             'libraries': [
               '-limm32.lib',