Add support for UIA accessibility interfaces like IAccessibleEx and IRawElementProviderSimple.

ui/base/accessibility/accessible_text_utils.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 "ui/base/accessibility/accessible_text_utils.h"
 
 #include "base/logging.h"
 #include "base/string_util.h"
 
 namespace ui {
@@ skipping 69 matching lines @@
     }
 
     if (direction == FORWARDS_DIRECTION) {
       result++;
     } else {
       result--;
     }
   }
 }
 
+#if defined(OS_WIN)
+// UIA TextProvider implementation.
+UIATextProvider::UIATextProvider()
+    : editable_(false) {}
+
+// static
+bool UIATextProvider::CreateTextProvider(bool editable, IUnknown** provider) {
+  CComObject<ui::UIATextProvider>* text_provider = NULL;
+  CComObject<ui::UIATextProvider>::CreateInstance(&text_provider);
+  DCHECK(text_provider);
+  text_provider->set_editable(true);

[dmazzoni, 2012/04/04 06:02:00]

set_editable(editable)

[ananta, 2012/04/04 19:23:00]

Done.

+  text_provider->AddRef();
+  HRESULT hr = text_provider->QueryInterface(

[dmazzoni, 2012/04/04 06:02:00]

Is this necessary? I think you should be able to just return text_provider
directly, like:

*provider = text_provider;

Then the Release() shouldn't be necessary.

[ananta, 2012/04/04 19:23:00]

That returns the following error.
error C2594: '=' : ambiguous conversions from 'ATL::CComObject<Base> *' to
'IUnknown *'

[dmazzoni, 2012/04/04 19:30:15]

This is because of the multiple inheritance. You should be able to cast
text_provider to ITextProvider first - that only has one path to IUnknown:

*provider = static_cast<ITextProvider*>(text_provider);

[ananta, 2012/04/04 21:40:17]

Done.

+      IID_IUnknown, reinterpret_cast<void**>(provider));
+  text_provider->Release();
+  return hr == S_OK;
+}
+
+STDMETHODIMP UIATextProvider::get_IsReadOnly(BOOL* read_only) {
+  *read_only = !editable_;
+  return S_OK;
+}
+#endif  // OS_WIN
 }  // Namespace ui