Create a visible window with class name Chrome_RenderWidgetHostHWND which corresponds to the bounds…

content/browser/accessibility/browser_accessibility_manager_win.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 "content/browser/accessibility/browser_accessibility_manager_win.h"
 
-#include <atlbase.h>
-#include <atlapp.h>
-#include <atlcom.h>
-#include <atlcrack.h>
-#include <oleacc.h>
-
 #include "base/command_line.h"
 #include "base/win/scoped_comptr.h"
 #include "base/win/windows_version.h"
 #include "content/browser/accessibility/browser_accessibility_state_impl.h"
 #include "content/browser/accessibility/browser_accessibility_win.h"
+#include "content/browser/renderer_host/legacy_render_widget_host_win.h"
 #include "content/common/accessibility_messages.h"
 
 namespace content {
 
-// Some screen readers expect every tab / every unique web content container
-// to be in its own HWND, like it was before Aura, but with Aura there's just
-// one main HWND for a frame, or even for the whole desktop. So, we need a
-// fake HWND as the root of the accessibility tree for each tab.
-// We should get rid of this code when the latest two versions of all
-// supported screen readers no longer make this assumption.
-//
-// This class implements a child HWND with zero size, that delegates its
-// accessibility implementation to the root of the BrowserAccessibilityManager
-// tree. This HWND is hooked up as the parent of the root object in the
-// BrowserAccessibilityManager tree, so when any accessibility client
-// calls ::WindowFromAccessibleObject, they get this HWND instead of the
-// DesktopWindowTreeHostWin.
-class AccessibleHWND
-    : public ATL::CWindowImpl<AccessibleHWND,
-                              ATL::CWindow,
-                              ATL::CWinTraits<WS_CHILD> > {
- public:
-  // Unfortunately, some screen readers look for this exact window class
-  // to enable certain features. It'd be great to remove this.
-  DECLARE_WND_CLASS_EX(L"Chrome_RenderWidgetHostHWND", CS_DBLCLKS, 0);
-
-  BEGIN_MSG_MAP_EX(AccessibleHWND)
-    MESSAGE_HANDLER_EX(WM_GETOBJECT, OnGetObject)
-  END_MSG_MAP()
-
-  AccessibleHWND(HWND parent, BrowserAccessibilityManagerWin* manager)
-      : manager_(manager) {
-    Create(parent);
-    ShowWindow(true);
-    MoveWindow(0, 0, 0, 0);
-
-    HRESULT hr = ::CreateStdAccessibleObject(
-        hwnd(), OBJID_WINDOW, IID_IAccessible,
-        reinterpret_cast<void **>(window_accessible_.Receive()));
-    DCHECK(SUCCEEDED(hr));
-  }
-
-  HWND hwnd() {
-    DCHECK(::IsWindow(m_hWnd));
-    return m_hWnd;
-  }
-
-  IAccessible* window_accessible() { return window_accessible_; }
-
-  void OnManagerDeleted() {
-    manager_ = NULL;
-  }
-
- protected:
-  virtual void OnFinalMessage(HWND hwnd) OVERRIDE {
-    if (manager_)
-      manager_->OnAccessibleHwndDeleted();
-    delete this;
-  }
-
- private:
-  LRESULT OnGetObject(UINT message,
-                      WPARAM w_param,
-                      LPARAM l_param) {
-    if (OBJID_CLIENT != l_param || !manager_)
-      return static_cast<LRESULT>(0L);
-
-    base::win::ScopedComPtr<IAccessible> root(
-        manager_->GetRoot()->ToBrowserAccessibilityWin());
-    return LresultFromObject(IID_IAccessible, w_param,
-        static_cast<IAccessible*>(root.Detach()));
-  }
-
-  BrowserAccessibilityManagerWin* manager_;
-  base::win::ScopedComPtr<IAccessible> window_accessible_;
-
-  DISALLOW_COPY_AND_ASSIGN(AccessibleHWND);
-};
-
-
 // static
 BrowserAccessibilityManager* BrowserAccessibilityManager::Create(
     const ui::AXNodeData& src,
     BrowserAccessibilityDelegate* delegate,
     BrowserAccessibilityFactory* factory) {
   return new BrowserAccessibilityManagerWin(
-      GetDesktopWindow(), NULL, src, delegate, factory);
+      new content::LegacyRenderWidgetHostHWND(GetDesktopWindow()), NULL, src,
+                                              delegate, factory);
 }
 
 BrowserAccessibilityManagerWin*
 BrowserAccessibilityManager::ToBrowserAccessibilityManagerWin() {
   return static_cast<BrowserAccessibilityManagerWin*>(this);
 }
 
 BrowserAccessibilityManagerWin::BrowserAccessibilityManagerWin(
-    HWND parent_hwnd,
+    LegacyRenderWidgetHostHWND* accessible_hwnd,
     IAccessible* parent_iaccessible,
     const ui::AXNodeData& src,
     BrowserAccessibilityDelegate* delegate,
     BrowserAccessibilityFactory* factory)
     : BrowserAccessibilityManager(src, delegate, factory),
-      parent_hwnd_(parent_hwnd),
+      parent_hwnd_(accessible_hwnd->parent()),

[cpu_(ooo_6.6-7.5), 2014/02/04 22:35:58]

I don't think parent_hwnd_ is used except in the previous code for creation so
we can remove it completely from this class.

[ananta, 2014/02/04 23:31:58]

Leaving this as is for now. This is used by accessibility unittests. Will look
into this in a subsequent CL.

       parent_iaccessible_(parent_iaccessible),
       tracked_scroll_object_(NULL),
-      accessible_hwnd_(NULL) {
+      accessible_hwnd_(accessible_hwnd) {
 }
 
 BrowserAccessibilityManagerWin::~BrowserAccessibilityManagerWin() {
   if (tracked_scroll_object_) {
     tracked_scroll_object_->Release();
     tracked_scroll_object_ = NULL;
   }
   if (accessible_hwnd_)
     accessible_hwnd_->OnManagerDeleted();
 }
 
 // static
 ui::AXNodeData BrowserAccessibilityManagerWin::GetEmptyDocument() {
   ui::AXNodeData empty_document;
   empty_document.id = 0;
   empty_document.role = ui::AX_ROLE_ROOT_WEB_AREA;
   empty_document.state =
       (1 << blink::WebAXStateEnabled) |
       (1 << ui::AX_STATE_READONLY) |
       (1 << ui::AX_STATE_BUSY);
   return empty_document;
 }
 
 void BrowserAccessibilityManagerWin::MaybeCallNotifyWinEvent(DWORD event,
                                                              LONG child_id) {
   // Don't fire events if this view isn't hooked up to its parent.
   if (!parent_iaccessible())
     return;
 
-  // If on Win 7 and complete accessibility is enabled, create a fake child HWND
+  // If on Win 7 and complete accessibility is enabled, use the fake child HWND
   // to use as the root of the accessibility tree. See comments above
-  // AccessibleHWND for details.
-  if (BrowserAccessibilityStateImpl::GetInstance()->IsAccessibleBrowser() &&
-      !accessible_hwnd_) {
-    accessible_hwnd_ = new AccessibleHWND(parent_hwnd_, this);
+  // LegacyRenderWidgetHostHWND for details.
+  if (BrowserAccessibilityStateImpl::GetInstance()->IsAccessibleBrowser()) {
+    DCHECK(accessible_hwnd_);
+    accessible_hwnd_->set_browser_accessibility_manager(this);
     parent_hwnd_ = accessible_hwnd_->hwnd();
     parent_iaccessible_ = accessible_hwnd_->window_accessible();
   }
-
   ::NotifyWinEvent(event, parent_hwnd(), OBJID_CLIENT, child_id);
 }
 
 void BrowserAccessibilityManagerWin::AddNodeToMap(BrowserAccessibility* node) {
   BrowserAccessibilityManager::AddNodeToMap(node);
   LONG unique_id_win = node->ToBrowserAccessibilityWin()->unique_id_win();
   unique_id_to_renderer_id_map_[unique_id_win] = node->renderer_id();
 }
 
 void BrowserAccessibilityManagerWin::RemoveNode(BrowserAccessibility* node) {
@@ skipping 139 matching lines @@
   // |parent_iaccessible_| are no longer valid either, since they were
   // derived from AccessibleHWND. We don't have to restore them to
   // previous values, though, because this should only happen
   // during the destruct sequence for this window.
   accessible_hwnd_ = NULL;
   parent_hwnd_ = NULL;
   parent_iaccessible_ = NULL;
 }
 
 }  // namespace content