Improve omnibox accessibility on Windows.

chrome/browser/ui/views/omnibox/omnibox_view_win.cc

 // Copyright (c) 2011 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.
 
 #include "chrome/browser/ui/views/omnibox/omnibox_view_win.h"
 
 #include <algorithm>
 #include <locale>
 #include <string>
 
 #include <richedit.h>
 #include <textserv.h>
 
 #include "base/auto_reset.h"
 #include "base/basictypes.h"
 #include "base/i18n/rtl.h"
 #include "base/lazy_instance.h"
 #include "base/memory/ref_counted.h"
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
 #include "base/win/iat_patch_function.h"
 #include "chrome/app/chrome_command_ids.h"
-#include "chrome/browser/autocomplete/autocomplete_accessibility.h"
 #include "chrome/browser/autocomplete/autocomplete_match.h"
 #include "chrome/browser/autocomplete/autocomplete_popup_model.h"
 #include "chrome/browser/autocomplete/keyword_provider.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/command_updater.h"
 #include "chrome/browser/net/url_fixer_upper.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/views/location_bar/location_bar_view.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "content/browser/tab_contents/tab_contents.h"
 #include "content/browser/user_metrics.h"
 #include "googleurl/src/url_util.h"
 #include "grit/generated_resources.h"
 #include "net/base/escape.h"
 #include "skia/ext/skia_utils_win.h"
+#include "ui/base/accessibility/accessible_view_state.h"
 #include "ui/base/clipboard/clipboard.h"
 #include "ui/base/clipboard/scoped_clipboard_writer.h"
 #include "ui/base/dragdrop/drag_drop_types.h"
 #include "ui/base/dragdrop/drag_source.h"
 #include "ui/base/dragdrop/drop_target.h"
 #include "ui/base/dragdrop/os_exchange_data.h"
 #include "ui/base/dragdrop/os_exchange_data_provider_win.h"
 #include "ui/base/events.h"
 #include "ui/base/keycodes/keyboard_codes.h"
 #include "ui/base/l10n/l10n_util.h"
@@ skipping 249 matching lines @@
   if (text_object_model_)
     text_object_model_->Undo(tomSuspend, NULL);
 }
 
 OmniboxViewWin::ScopedSuspendUndo::~ScopedSuspendUndo() {
   // Resume Undo processing.
   if (text_object_model_)
     text_object_model_->Undo(tomResume, NULL);
 }
 
+// A subclass of NativeViewHost that provides accessibility info for the
+// underlying Omnibox view.
+class OmniboxViewWrapper : public views::NativeViewHost {
+ public:
+  explicit OmniboxViewWrapper(OmniboxViewWin* omnibox_view_win)
+      : omnibox_view_win_(omnibox_view_win) { }
+
+  gfx::NativeViewAccessible GetNativeViewAccessible() {
+    // This forces it to use NativeViewAccessibilityWin rather than
+    // any accessibility provided natively by the HWND.
+    return View::GetNativeViewAccessible();
+  }
+
+  // views::View
+  virtual void GetAccessibleState(ui::AccessibleViewState* state) {
+    state->name = l10n_util::GetStringUTF16(IDS_ACCNAME_LOCATION);
+    state->role = ui::AccessibilityTypes::ROLE_TEXT;
+    state->value = omnibox_view_win_->GetText();
+    state->state = ui::AccessibilityTypes::STATE_EDITABLE;
+    size_t sel_start;
+    size_t sel_end;
+    omnibox_view_win_->GetSelectionBounds(&sel_start, &sel_end);
+    state->selection_start = sel_start;
+    state->selection_end = sel_end;

[sky, 2011/10/25 20:08:45]

Is this ok if sel_start > sel_end?

[dmazzoni, 2011/10/26 16:46:13]

Yes, I tested creating a selection using shift+right and shift+left from a
cursor and they both work.

+  }
+
+ private:
+  OmniboxViewWin* omnibox_view_win_;
+};

[sky, 2011/10/25 20:08:45]

DISALLOW_COPY_AND_ASSIGN

[dmazzoni, 2011/10/26 16:46:13]

Done.

+
 ///////////////////////////////////////////////////////////////////////////////
 // OmniboxViewWin
 
 namespace {
 
 // These are used to hook the CRichEditCtrl's calls to BeginPaint() and
 // EndPaint() and provide a memory DC instead.  See OnPaint().
 HWND edit_hwnd = NULL;
 PAINTSTRUCT paint_struct;
 
@@ skipping 341 matching lines @@
   CHARRANGE selection;
   GetSel(selection);
   return IsSelectAllForRange(selection);
 }
 
 bool OmniboxViewWin::DeleteAtEndPressed() {
   return delete_at_end_pressed_;
 }
 
 void OmniboxViewWin::GetSelectionBounds(string16::size_type* start,
-                                        string16::size_type* end) {
+                                        string16::size_type* end) const {
   CHARRANGE selection;
   GetSel(selection);
   *start = static_cast<size_t>(selection.cpMin);
   *end = static_cast<size_t>(selection.cpMax);
 }
 
 void OmniboxViewWin::SelectAll(bool reversed) {
   if (reversed)
     SetSelection(GetTextLength(), 0);
   else
@@ skipping 36 matching lines @@
 }
 
 void OmniboxViewWin::ClosePopup() {
   model_->StopAutocomplete();
 }
 
 void OmniboxViewWin::SetFocus() {
   ::SetFocus(m_hWnd);
 }
 
-IAccessible* OmniboxViewWin::GetIAccessible() {
-  if (!autocomplete_accessibility_) {
-    CComObject<AutocompleteAccessibility>* accessibility = NULL;
-    if (!SUCCEEDED(CComObject<AutocompleteAccessibility>::CreateInstance(
-            &accessibility)) || !accessibility)
-      return NULL;
-
-    // Wrap the created object in a smart pointer so it won't leak.
-    base::win::ScopedComPtr<IAccessible> accessibility_comptr(accessibility);
-    if (!SUCCEEDED(accessibility->Initialize(this)))
-      return NULL;
-
-    // Copy to the class smart pointer, and notify that an instance of
-    // IAccessible was allocated for m_hWnd.
-    autocomplete_accessibility_ = accessibility_comptr;
-    NotifyWinEvent(EVENT_OBJECT_CREATE, m_hWnd, OBJID_CLIENT, CHILDID_SELF);
-  }
-  // Detach to leave ref counting to the caller.
-  return autocomplete_accessibility_.Detach();
-}
-
 void OmniboxViewWin::SetDropHighlightPosition(int position) {
   if (drop_highlight_position_ != position) {
     RepaintDropHighlight(drop_highlight_position_);
     drop_highlight_position_ = position;
     RepaintDropHighlight(drop_highlight_position_);
   }
 }
 
 void OmniboxViewWin::MoveSelectedText(int new_position) {
   const string16 selected_text(GetSelectedText());
@@ skipping 120 matching lines @@
 
   if (selection_differs)
     controller_->OnSelectionBoundsChanged();
 
   if (something_changed && text_differs)
     TextChanged();
 
   if (text_differs) {
     // Note that a TEXT_CHANGED event implies that the cursor/selection
     // probably changed too, so we don't need to send both.
-    parent_view_->GetWidget()->NotifyAccessibilityEvent(
-        parent_view_, ui::AccessibilityTypes::EVENT_TEXT_CHANGED, true);
+    native_view_host_->GetWidget()->NotifyAccessibilityEvent(
+        native_view_host_, ui::AccessibilityTypes::EVENT_TEXT_CHANGED, true);
   } else if (selection_differs) {
     // Notify assistive technology that the cursor or selection changed.
-    parent_view_->GetWidget()->NotifyAccessibilityEvent(
-        parent_view_, ui::AccessibilityTypes::EVENT_SELECTION_CHANGED, true);
+    native_view_host_->GetWidget()->NotifyAccessibilityEvent(
+        native_view_host_,
+        ui::AccessibilityTypes::EVENT_SELECTION_CHANGED,
+        true);
   } else if (delete_at_end_pressed_) {
     model_->OnChanged();
   }
 
   return something_changed;
 }
 
 gfx::NativeView OmniboxViewWin::GetNativeView() const {
   return m_hWnd;
 }
@@ skipping 36 matching lines @@
   bool ime_composing = false;
   HIMC context = ImmGetContext(m_hWnd);
   if (context) {
     ime_composing = !!ImmGetCompositionString(context, GCS_COMPSTR, NULL, 0);
     ImmReleaseContext(m_hWnd, context);
   }
   return ime_composing;
 }
 
 views::View* OmniboxViewWin::AddToView(views::View* parent) {
-  views::NativeViewHost* host = new views::NativeViewHost;
-  parent->AddChildView(host);
-  host->set_focus_view(parent);
-  host->Attach(GetNativeView());
-  return host;
+  native_view_host_ = new OmniboxViewWrapper(this);
+  parent->AddChildView(native_view_host_);
+  native_view_host_->set_focus_view(parent);

[David Tseng, 2011/10/25 21:55:25]

On Windows, is the focused view the parent? (LocationBarView). Perhaps it should
be the NativeViewHost?

[dmazzoni, 2011/10/26 16:46:13]

I think this doesn't affect native focus, it just indicates that the parent is
the one keeping track of views focus.

[David Tseng, 2011/10/27 20:42:16]

Ok; I did see two native IAccessible's with focused state; not sure if this is
an issue, but at least with screen readers, things appear fine.

+  native_view_host_->Attach(GetNativeView());
+  return native_view_host_;
 }
 
 int OmniboxViewWin::OnPerformDrop(const views::DropTargetEvent& event) {
   return OnPerformDropImpl(event, false);
 }
 
 int OmniboxViewWin::OnPerformDropImpl(const views::DropTargetEvent& event,
                                       bool in_drag) {
   const ui::OSExchangeData& data = event.data();
 
@@ skipping 358 matching lines @@
 }
 
 void OmniboxViewWin::OnCut() {
   OnCopy();
 
   // This replace selection will have no effect (even on the undo stack) if the
   // current selection is empty.
   ReplaceSel(L"", true);
 }
 
-LRESULT OmniboxViewWin::OnGetObject(UINT uMsg,
+LRESULT OmniboxViewWin::OnGetObject(UINT message,
                                     WPARAM wparam,
                                     LPARAM lparam) {
-  // Accessibility readers will send an OBJID_CLIENT message.
+  // This is a request for the native accessibility object.
   if (lparam == OBJID_CLIENT) {
-    // Re-attach for internal re-usage of accessibility pointer.
-    autocomplete_accessibility_.Attach(GetIAccessible());
-
-    if (autocomplete_accessibility_) {
-      return LresultFromObject(IID_IAccessible, wparam,
-                               autocomplete_accessibility_);
-    }
+    return LresultFromObject(IID_IAccessible, wparam,
+                             native_view_host_->GetNativeViewAccessible());
   }
   return 0;
 }
 
 LRESULT OmniboxViewWin::OnImeComposition(UINT message,
                                          WPARAM wparam,
                                          LPARAM lparam) {
   if (ignore_ime_messages_) {
     // This message was sent while we're in the middle of meddling with the
     // underlying edit control.  If we handle it below, OnAfterPossibleChange()
@@ skipping 1257 matching lines @@
   // PosFromChar(i) might return 0 when i is greater than 1.
   return font_.GetStringWidth(text) + GetHorizontalMargin();
 }
 
 bool OmniboxViewWin::IsCaretAtEnd() const {
   long length = GetTextLength();
   CHARRANGE sel;
   GetSelection(sel);
   return sel.cpMin == sel.cpMax && sel.cpMin == length;
 }