Added a class acting as a fake caret for accessibility.

ui/views/win/hwnd_message_handler.cc

 // 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.
 
 #include "ui/views/win/hwnd_message_handler.h"
 
+#include <atlbase.h>
+#include <atlcom.h>
 #include <dwmapi.h>
 #include <oleacc.h>
 #include <shellapi.h>
 #include <tchar.h>
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/debug/alias.h"
 #include "base/location.h"
 #include "base/macros.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
 #include "base/trace_event/trace_event.h"
 #include "base/win/scoped_gdi_object.h"
 #include "base/win/windows_version.h"
+#include "ui/accessibility/platform/ax_fake_caret_win.h"
 #include "ui/base/view_prop.h"
 #include "ui/base/win/internal_constants.h"
 #include "ui/base/win/lock_state.h"
 #include "ui/base/win/mouse_wheel_util.h"
 #include "ui/base/win/shell.h"
 #include "ui/base/win/touch_input.h"
 #include "ui/display/win/dpi.h"
 #include "ui/display/win/screen_win.h"
 #include "ui/events/event.h"
 #include "ui/events/event_utils.h"
@@ skipping 1468 matching lines @@
 
   // Only the lower 32 bits of l_param are valid when checking the object id
   // because it sometimes gets sign-extended incorrectly (but not always).
   DWORD obj_id = static_cast<DWORD>(static_cast<DWORD_PTR>(l_param));
 
   // Accessibility readers will send an OBJID_CLIENT message
   if (static_cast<DWORD>(OBJID_CLIENT) == obj_id) {
     // Retrieve MSAA dispatch object for the root view.
     base::win::ScopedComPtr<IAccessible> root(
         delegate_->GetNativeViewAccessible());
-
-    // Create a reference that MSAA will marshall to the client.
     reference_result = LresultFromObject(IID_IAccessible, w_param,
         static_cast<IAccessible*>(root.Detach()));
+  } else if (static_cast<DWORD>(OBJID_CARET) == obj_id) {
+    // Used by some assistive software to retrieve the location of the caret.
+    CComObjectStack<ui::AXFakeCaretWin> fake_caret;
+    DCHECK_EQ(fake_caret.m_hResFinalConstruct, S_OK);
+    reference_result = LresultFromObject(
+        IID_IAccessible, w_param, static_cast<IAccessible*>(&fake_caret));
   }
 
   return reference_result;
 }
 
 LRESULT HWNDMessageHandler::OnImeMessages(UINT message,
                                           WPARAM w_param,
                                           LPARAM l_param) {
   LRESULT result = 0;
   base::WeakPtr<HWNDMessageHandler> ref(weak_factory_.GetWeakPtr());
@@ skipping 1256 matching lines @@
   MONITORINFO monitor_info = {sizeof(monitor_info)};
   GetMonitorInfo(MonitorFromWindow(hwnd(), MONITOR_DEFAULTTOPRIMARY),
                  &monitor_info);
   gfx::Rect shrunk_rect(monitor_info.rcMonitor);
   shrunk_rect.set_height(shrunk_rect.height() - 1);
   background_fullscreen_hack_ = true;
   SetBoundsInternal(shrunk_rect, false);
 }
 
 }  // namespace views