Adds propagation and handling of render-side focus events, for the benefit of assistive technologies (accessibility). Also cleans up the handling of WM_GETOBJECT in RenderWidgetHostViewWin and WidgetWin, as well as in BrowserAccessibilityManager.

Review URL: http://codereview.chromium.org/115374

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@16449 0039d316-1c4b-4281-b951-d872f2087c98

22 files changed, 380 insertions, 266 deletions

diff --git a/chrome/browser/browser_accessibility.cc b/chrome/browser/browser_accessibility.cc
index af56972..9fade8d 100644
--- a/chrome/browser/browser_accessibility.cc
+++ b/chrome/browser/browser_accessibility.cc
@@ -9,15 +9,29 @@
 
 using webkit_glue::WebAccessibility;
 
-BrowserAccessibility::BrowserAccessibility()
-    : iaccessible_id_(-1),
-      instance_active_(true) {
+HRESULT BrowserAccessibility::Initialize(int iaccessible_id, int routing_id,
+                                         int process_id, HWND parent_hwnd) {
+  if (!parent_hwnd || iaccessible_id < 0)
+    return E_INVALIDARG;
+
+  iaccessible_id_ = iaccessible_id;
+  routing_id_ = routing_id;
+  process_id_ = process_id;
+  parent_hwnd_ = parent_hwnd;
+
+  // Mark instance as active.
+  instance_active_ = true;
+
+  // Treat child ids intitially as referring to direct children of the object.
+  direct_descendant_ = true;
+
+  return S_OK;
 }
 
 HRESULT BrowserAccessibility::accDoDefaultAction(VARIANT var_id) {
   if (!instance_active()) {
     // Instance no longer active, fail gracefully.
-    // TODO(klink): Once we have MSAA events, change these fails for having
+    // TODO(klink): Once we have MSAA events, change these fails to having
     // BrowserAccessibilityManager firing the right event.
     return E_FAIL;
   }
@@ -46,7 +60,7 @@ STDMETHODIMP BrowserAccessibility::accHitTest(LONG x_left, LONG y_top,
   if (!child)
     return E_INVALIDARG;
 
-  if (!parent_hwnd()) {
+  if (!parent_hwnd_) {
     // Parent HWND needed for coordinate conversion.
     return E_FAIL;
   }
@@ -54,7 +68,7 @@ STDMETHODIMP BrowserAccessibility::accHitTest(LONG x_left, LONG y_top,
   // Convert coordinates to test from screen into client window coordinates, to
   // maintain sandbox functionality on renderer side.
   POINT p = {x_left, y_top};
-  ::ScreenToClient(parent_hwnd(), &p);
+  ::ScreenToClient(parent_hwnd_, &p);
 
   if (!RequestAccessibilityInfo(WebAccessibility::FUNCTION_HITTEST,
                                 EmptyVariant(), p.x, p.y)) {
@@ -93,7 +107,7 @@ STDMETHODIMP BrowserAccessibility::accLocation(LONG* x_left, LONG* y_top,
   }
 
   if (var_id.vt != VT_I4 || !x_left || !y_top || !width || !height ||
-      !parent_hwnd()) {
+      !parent_hwnd_) {
     return E_INVALIDARG;
   }
 
@@ -106,7 +120,7 @@ STDMETHODIMP BrowserAccessibility::accLocation(LONG* x_left, LONG* y_top,
 
   // Find the top left corner of the containing window in screen coords, and
   // adjust the output position by this amount.
-  ::ClientToScreen(parent_hwnd(), &top_left);
+  ::ClientToScreen(parent_hwnd_, &top_left);
 
   *x_left = response().output_long1 + top_left.x;
   *y_top  = response().output_long2 + top_left.y;
@@ -393,15 +407,15 @@ STDMETHODIMP BrowserAccessibility::get_accParent(IDispatch** disp_parent) {
     return E_FAIL;
   }
 
-  if (!disp_parent || !parent_hwnd())
+  if (!disp_parent || !parent_hwnd_)
     return E_INVALIDARG;
 
   // Root node's parent is the containing HWND's IAccessible.
-  if (iaccessible_id() == 0) {
+  if (iaccessible_id_ == 0) {
     // For an object that has no parent (e.g. root), point the accessible parent
     // to the default implementation.
     HRESULT hr =
-        ::CreateStdAccessibleObject(parent_hwnd(), OBJID_WINDOW,
+        ::CreateStdAccessibleObject(parent_hwnd_, OBJID_WINDOW,
                                     IID_IAccessible,
                                     reinterpret_cast<void**>(disp_parent));
 
@@ -498,20 +512,15 @@ STDMETHODIMP BrowserAccessibility::get_accValue(VARIANT var_id, BSTR* value) {
   return S_OK;
 }
 
-STDMETHODIMP BrowserAccessibility::accSelect(LONG flags_select,
-                                             VARIANT var_id) {
-  return E_NOTIMPL;
-}
-
 STDMETHODIMP BrowserAccessibility::get_accHelpTopic(BSTR* help_file,
                                                     VARIANT var_id,
                                                     LONG* topic_id) {
-  if (help_file) {
+  if (help_file)
     *help_file = NULL;
-  }
-  if (topic_id) {
+
+  if (topic_id)
     *topic_id = static_cast<LONG>(-1);
-  }
+
   return E_NOTIMPL;
 }
 
@@ -522,38 +531,38 @@ STDMETHODIMP BrowserAccessibility::get_accSelection(VARIANT* selected) {
   return E_NOTIMPL;
 }
 
-STDMETHODIMP BrowserAccessibility::put_accName(VARIANT var_id, BSTR put_name) {
-  return E_NOTIMPL;
-}
-
-STDMETHODIMP BrowserAccessibility::put_accValue(VARIANT var_id, BSTR put_val) {
-  return E_NOTIMPL;
-}
-
 STDMETHODIMP BrowserAccessibility::CreateInstance(REFIID iid,
                                                   int iaccessible_id,
                                                   void** interface_ptr) {
   return BrowserAccessibilityManager::GetInstance()->
-      CreateAccessibilityInstance(iid, iaccessible_id, instance_id(),
-                                  interface_ptr);
+      CreateAccessibilityInstance(iid, iaccessible_id, routing_id_,
+                                  process_id_, parent_hwnd_, interface_ptr);
 }
 
 bool BrowserAccessibility::RequestAccessibilityInfo(int iaccessible_func_id,
                                                     VARIANT var_id, LONG input1,
                                                     LONG input2) {
-  return BrowserAccessibilityManager::GetInstance()->RequestAccessibilityInfo(
-      iaccessible_id(), instance_id(), iaccessible_func_id, var_id.lVal, input1,
-      input2);
+  // Create and populate IPC message structure, for retrieval of accessibility
+  // information from the renderer.
+  WebAccessibility::InParams in_params;
+  in_params.object_id = iaccessible_id_;
+  in_params.function_id = iaccessible_func_id;
+  in_params.child_id = var_id.lVal;
+  in_params.direct_descendant = direct_descendant();
+  in_params.input_long1 = input1;
+  in_params.input_long2 = input2;
+
+  if (!direct_descendant())
+    set_direct_descendant(true);
+
+  return BrowserAccessibilityManager::GetInstance()->
+      RequestAccessibilityInfo(&in_params, routing_id_, process_id_);
 }
 
 const WebAccessibility::OutParams& BrowserAccessibility::response() {
   return BrowserAccessibilityManager::GetInstance()->response();
 }
 
-HWND BrowserAccessibility::parent_hwnd() {
-  return BrowserAccessibilityManager::GetInstance()->parent_hwnd(instance_id());
-}
-
 long BrowserAccessibility::MSAARole(long browser_accessibility_role) {
   switch (browser_accessibility_role) {
     case WebAccessibility::ROLE_PUSHBUTTON :
diff --git a/chrome/browser/browser_accessibility.h b/chrome/browser/browser_accessibility.h
index 8b56662..c8d4187 100644
--- a/chrome/browser/browser_accessibility.h
+++ b/chrome/browser/browser_accessibility.h
@@ -10,7 +10,6 @@
 
 #include <oleacc.h>
 
-#include "base/basictypes.h"
 #include "webkit/glue/webaccessibility.h"
 
 using webkit_glue::WebAccessibility;
@@ -33,9 +32,14 @@ class ATL_NO_VTABLE BrowserAccessibility
     COM_INTERFACE_ENTRY(IAccessible)
   END_COM_MAP()
 
-  BrowserAccessibility();
+  BrowserAccessibility() {}
   ~BrowserAccessibility() {}
 
+  HRESULT Initialize(int iaccessible_id,
+                     int routing_id,
+                     int process_id,
+                     HWND parent_hwnd);
+
   // Supported IAccessible methods.
 
   // Performs the default action on a given object.
@@ -91,7 +95,7 @@ class ATL_NO_VTABLE BrowserAccessibility
   STDMETHODIMP get_accValue(VARIANT var_id, BSTR* value);
 
   // Non-supported (by WebKit) IAccessible methods.
-  STDMETHODIMP accSelect(LONG flags_sel, VARIANT var_id);
+  STDMETHODIMP accSelect(LONG flags_sel, VARIANT var_id) { return E_NOTIMPL; }
 
   STDMETHODIMP get_accHelpTopic(BSTR* help_file,
                                 VARIANT var_id,
@@ -100,20 +104,11 @@ class ATL_NO_VTABLE BrowserAccessibility
   STDMETHODIMP get_accSelection(VARIANT* selected);
 
   // Deprecated functions, not implemented here.
-  STDMETHODIMP put_accName(VARIANT var_id, BSTR put_name);
-  STDMETHODIMP put_accValue(VARIANT var_id, BSTR put_val);
-
-  // Modify/retrieve the unique id of this IAccessible instance.
-  void set_iaccessible_id(int iaccessible_id) {
-    iaccessible_id_ = iaccessible_id;
-  }
-  int iaccessible_id() const { return iaccessible_id_; }
+  STDMETHODIMP put_accName(VARIANT var_id, BSTR put_name) { return E_NOTIMPL; }
+  STDMETHODIMP put_accValue(VARIANT var_id, BSTR put_val) { return E_NOTIMPL; }
 
-  // Modify/retrieve the unique id of this IAccessible's routing variables.
-  void set_instance_id(int instance_id) {
-    instance_id_ = instance_id;
-  }
-  int instance_id() const { return instance_id_; }
+  // Accessors/mutators.
+  HWND parent_hwnd() const { return parent_hwnd_;}
 
   // Modify/retrieve the state (active/inactive) of this instance.
   void set_instance_active(bool instance_active) {
@@ -121,6 +116,13 @@ class ATL_NO_VTABLE BrowserAccessibility
   }
   int instance_active() const { return instance_active_; }
 
+  void set_direct_descendant(bool direct_descendant) {
+    direct_descendant_ = direct_descendant;
+  }
+  bool direct_descendant() const { return direct_descendant_; }
+
+  int routing_id() const { return routing_id_; }
+
  private:
   // Creates an empty VARIANT. Used as the equivalent of a NULL (unused) input
   // parameter.
@@ -148,7 +150,6 @@ class ATL_NO_VTABLE BrowserAccessibility
 
   // Accessors.
   const WebAccessibility::OutParams& response();
-  HWND parent_hwnd();
 
   // Returns a conversion from the BrowserAccessibilityRole (as defined in
   // webkit/glue/webaccessibility.h) to an MSAA role.
@@ -162,10 +163,21 @@ class ATL_NO_VTABLE BrowserAccessibility
   // mapping it to the correct IAccessible on that side. Initialized to -1.
   int iaccessible_id_;
 
-  // The unique id of this IAccessible instance. Used to help
+  // The unique ids of this IAccessible instance. Used to help
   // BrowserAccessibilityManager instance retrieve the correct member
   // variables for this process.
-  int instance_id_;
+  int routing_id_;
+  int process_id_;
+
+  HWND parent_hwnd_;
+
+  // Indicates if an incoming request for child information relates to a child
+  // id of a direct child of the BrowserAccessibility object, or if it refers
+  // to an object elsewhere in the MSAA tree. Set by BrowserAccessibilityManager
+  // and applicable only to the root BrowserAccessibility object (id 0). Needed
+  // to properly handled MSAA focus events, where the child id is the only
+  // parameter in our control.
+  bool direct_descendant_;
 
   // The instance should only be active if there is a non-terminated
   // RenderProcessHost associated with it. The BrowserAccessibilityManager keeps
diff --git a/chrome/browser/browser_accessibility_manager.cc b/chrome/browser/browser_accessibility_manager.cc
index e97e0e4..0930024 100644
--- a/chrome/browser/browser_accessibility_manager.cc
+++ b/chrome/browser/browser_accessibility_manager.cc
@@ -6,7 +6,7 @@
 
 #include "chrome/browser/browser_accessibility.h"
 #include "chrome/browser/renderer_host/render_process_host.h"
-#include "chrome/browser/renderer_host/render_widget_host.h"
+#include "chrome/browser/renderer_host/render_view_host.h"
 #include "chrome/common/notification_service.h"
 #include "chrome/common/render_messages.h"
 
@@ -21,16 +21,14 @@ BrowserAccessibilityManager* BrowserAccessibilityManager::GetInstance() {
   return Singleton<BrowserAccessibilityManager>::get();
 }
 
-BrowserAccessibilityManager::BrowserAccessibilityManager()
-    : instance_id_(0) {
+BrowserAccessibilityManager::BrowserAccessibilityManager() {
   NotificationService::current()->AddObserver(this,
       NotificationType::RENDERER_PROCESS_TERMINATED,
       NotificationService::AllSources());
 }
 
 BrowserAccessibilityManager::~BrowserAccessibilityManager() {
-  // Clear hashmaps.
-  instance_map_.clear();
+  // Clear hashmap.
   render_process_host_map_.clear();
 
   // We don't remove ourselves as an observer because we are a Singleton object,
@@ -38,7 +36,8 @@ BrowserAccessibilityManager::~BrowserAccessibilityManager() {
 }
 
 STDMETHODIMP BrowserAccessibilityManager::CreateAccessibilityInstance(
-    REFIID iid, int acc_obj_id, int instance_id, void** interface_ptr) {
+    REFIID iid, int acc_obj_id, int routing_id, int process_id,
+    HWND parent_hwnd, void** interface_ptr) {
   if (IID_IUnknown == iid || IID_IDispatch == iid || IID_IAccessible == iid) {
     CComObject<BrowserAccessibility>* instance = NULL;
 
@@ -50,21 +49,16 @@ STDMETHODIMP BrowserAccessibilityManager::CreateAccessibilityInstance(
 
     CComPtr<IAccessible> accessibility_instance(instance);
 
-    // Set unique ids.
-    instance->set_iaccessible_id(acc_obj_id);
-    instance->set_instance_id(instance_id);
+    // Set class member variables.
+    instance->Initialize(acc_obj_id, routing_id, process_id, parent_hwnd);
 
-    // Retrieve the RenderWidgetHost connected to this request.
-    InstanceMap::iterator it = instance_map_.find(instance_id);
+    // Retrieve the RenderViewHost connected to this request.
+    RenderViewHost* rvh = RenderViewHost::FromID(process_id, routing_id);
 
-    if (it != instance_map_.end()) {
-      UniqueMembers* members = it->second;
-
-      if (!members || !members->render_widget_host_)
-        return E_FAIL;
-
-      render_process_host_map_[members->render_widget_host_->process()] =
-          instance;
+    // Update cache with RenderProcessHost/BrowserAccessibility pair.
+    if (rvh && rvh->process()) {
+      render_process_host_map_.insert(
+          MapEntry(rvh->process()->pid(), instance));
     } else {
       // No RenderProcess active for this instance.
       return E_FAIL;
@@ -80,73 +74,71 @@ STDMETHODIMP BrowserAccessibilityManager::CreateAccessibilityInstance(
 }
 
 bool BrowserAccessibilityManager::RequestAccessibilityInfo(
-    int acc_obj_id, int instance_id, int acc_func_id, int child_id, long input1,
-    long input2) {
+    WebAccessibility::InParams* in, int routing_id, int process_id) {
   // Create and populate IPC message structure, for retrieval of accessibility
   // information from the renderer.
   WebAccessibility::InParams in_params;
-  in_params.object_id = acc_obj_id;
-  in_params.function_id = acc_func_id;
-  in_params.child_id = child_id;
-  in_params.input_long1 = input1;
-  in_params.input_long2 = input2;
-
-  // Retrieve the RenderWidgetHost connected to this request.
-  InstanceMap::iterator it = instance_map_.find(instance_id);
-
-  if (it == instance_map_.end()) {
-    // Id not found.
-    return false;
-  }
+  in_params.object_id = in->object_id;
+  in_params.function_id = in->function_id;
+  in_params.child_id = in->child_id;
+  in_params.direct_descendant = in->direct_descendant;
+  in_params.input_long1 = in->input_long1;
+  in_params.input_long2 = in->input_long2;
 
-  UniqueMembers* members = it->second;
-
-  if (!members || !members->render_widget_host_)
-    return false;
+  // Retrieve the RenderViewHost connected to this request.
+  RenderViewHost* rvh = RenderViewHost::FromID(process_id, routing_id);
 
+  // Send accessibility information retrieval message to the renderer.
   bool success = false;
-  if (members->render_widget_host_->process() &&
-      members->render_widget_host_->process()->channel()) {
+  if (rvh && rvh->process() && rvh->process()->channel()) {
     IPC::SyncMessage* msg =
-        new ViewMsg_GetAccessibilityInfo(members->render_widget_host_->
-            routing_id(), in_params, &out_params_);
+        new ViewMsg_GetAccessibilityInfo(routing_id, in_params, &out_params_);
     // Necessary for the send to keep the UI responsive.
     msg->EnableMessagePumping();
-    success = members->render_widget_host_->process()->channel()->
-        SendWithTimeout(msg, kAccessibilityMessageTimeOut);
+    success = rvh->process()->channel()->SendWithTimeout(msg,
+        kAccessibilityMessageTimeOut);
   }
   return success;
 }
 
+bool BrowserAccessibilityManager::ChangeAccessibilityFocus(int acc_obj_id,
+                                                           int process_id,
+                                                           int routing_id) {
+  BrowserAccessibility* browser_acc =
+      GetBrowserAccessibility(process_id, routing_id);
+  if (browser_acc) {
+    // Indicate that the request for child information is referring to a non-
+    // direct descendant of the root.
+    browser_acc->set_direct_descendant(false);
+
+    // Notify Access Technology that there was a change in keyboard focus.
+    ::NotifyWinEvent(EVENT_OBJECT_FOCUS, browser_acc->parent_hwnd(),
+                     OBJID_CLIENT, static_cast<LONG>(acc_obj_id));
+    return true;
+  }
+  return false;
+}
+
 const WebAccessibility::OutParams& BrowserAccessibilityManager::response() {
   return out_params_;
 }
 
-HWND BrowserAccessibilityManager::parent_hwnd(int id) {
-  // Retrieve the parent HWND connected to the requester's id.
-  InstanceMap::iterator it = instance_map_.find(id);
-
-  if (it == instance_map_.end()) {
-    // Id not found.
-    return NULL;
-  }
-
-  UniqueMembers* members = it->second;
+BrowserAccessibility* BrowserAccessibilityManager::GetBrowserAccessibility(
+    int process_id, int routing_id) {
+  // Retrieve the BrowserAccessibility connected to the requester's id. There
+  // could be multiple BrowserAccessibility connected to the given |process_id|,
+  // but they all have the same parent HWND, so using the first hit is fine.
+  RenderProcessHostMap::iterator it =
+      render_process_host_map_.lower_bound(process_id);
 
-  if (!members || !members->parent_hwnd_)
-    return NULL;
+  RenderProcessHostMap::iterator end_of_matching_objects =
+    render_process_host_map_.upper_bound(process_id);
 
-  return members->parent_hwnd_;
-}
-
-int BrowserAccessibilityManager::SetMembers(BrowserAccessibility* browser_acc,
-    HWND parent_hwnd, RenderWidgetHost* render_widget_host) {
-  // Set HWND and RenderWidgetHost connected to |browser_acc|.
-  instance_map_[instance_id_] =
-      new UniqueMembers(parent_hwnd, render_widget_host);
-
-  render_process_host_map_[render_widget_host->process()] = browser_acc;
-  return instance_id_++;
+  for (; it != end_of_matching_objects; ++it) {
+    if (it->second && it->second->routing_id() == routing_id)
+      return it->second;
+  }
+  return NULL;
 }
 
 void BrowserAccessibilityManager::Observe(NotificationType type,
@@ -155,22 +147,18 @@ void BrowserAccessibilityManager::Observe(NotificationType type,
   DCHECK(type == NotificationType::RENDERER_PROCESS_TERMINATED);
   RenderProcessHost* rph = Source<RenderProcessHost>(source).ptr();
   DCHECK(rph);
-  RenderProcessHostMap::iterator it = render_process_host_map_.find(rph);
 
-  if (it == render_process_host_map_.end() || !it->second) {
-    // RenderProcessHost not associated with any BrowserAccessibility instance.
-    return;
-  }
+  RenderProcessHostMap::iterator it =
+      render_process_host_map_.lower_bound(rph->pid());
 
-  // Set BrowserAccessibility instance to inactive state.
-  it->second->set_instance_active(false);
+  RenderProcessHostMap::iterator end_of_matching_objects =
+    render_process_host_map_.upper_bound(rph->pid());
 
-  // Delete entry also from InstanceMap.
-  InstanceMap::iterator it2 = instance_map_.find(it->second->instance_id());
-
-  if (it2 != instance_map_.end())
-    instance_map_.erase(it2);
-
-  // Only delete the first entry once it is no longer in use.
-  render_process_host_map_.erase(it);
+  for (; it != end_of_matching_objects; ++it) {
+    if (it->second) {
+      // Set all matching BrowserAccessibility instances to inactive state.
+      // TODO(klink): Do more active memory cleanup as well.
+      it->second->set_instance_active(false);
+    }
+  }
 }
diff --git a/chrome/browser/browser_accessibility_manager.h b/chrome/browser/browser_accessibility_manager.h
index defcb9e..081f978 100644
--- a/chrome/browser/browser_accessibility_manager.h
+++ b/chrome/browser/browser_accessibility_manager.h
@@ -5,8 +5,7 @@
 #ifndef CHROME_BROWSER_BROWSER_ACCESSIBILITY_MANAGER_H_
 #define CHROME_BROWSER_BROWSER_ACCESSIBILITY_MANAGER_H_
 
-#include <oaidl.h>  // Needed for VARIANT structure.
-#include <hash_map>
+#include <map>
 
 #include "base/singleton.h"
 #include "chrome/common/notification_observer.h"
@@ -16,6 +15,8 @@ class BrowserAccessibility;
 class RenderProcessHost;
 class RenderWidgetHost;
 
+using webkit_glue::WebAccessibility;
+
 ////////////////////////////////////////////////////////////////////////////////
 //
 // BrowserAccessibilityManager
@@ -35,35 +36,28 @@ class BrowserAccessibilityManager : public NotificationObserver {
   static BrowserAccessibilityManager* GetInstance();
 
   // Creates an instance of BrowserAccessibility, initializes it and sets the
-  // [acc_obj_id], which is used for IPC communication, and [instance_id],
+  // |acc_obj_id|, which is used for IPC communication, and |instance_id|,
   // which is used to identify the mapping between accessibility instance and
   // RenderProcess.
   STDMETHODIMP CreateAccessibilityInstance(REFIID iid,
                                            int acc_obj_id,
-                                           int instance_id,
+                                           int routing_id,
+                                           int process_id,
+                                           HWND parent_hwnd,
                                            void** interface_ptr);
 
   // Composes and sends a message for requesting needed accessibility
-  // information. Unused LONG input parameters should be NULL, and the VARIANT
-  // [var_id] an empty, valid instance.
-  bool RequestAccessibilityInfo(int acc_obj_id,
-                                int instance_id,
-                                int acc_func_id,
-                                int child_id,
-                                long input1,
-                                long input2);
-
-  // Wrapper function, for cleaner code.
-  const webkit_glue::WebAccessibility::OutParams& response();
+  // information.
+  bool RequestAccessibilityInfo(WebAccessibility::InParams* in,
+                                int routing_id,
+                                int process_id);
 
-  // Retrieves the parent HWND connected to the provided id.
-  HWND parent_hwnd(int id);
+  // Notifies assistive technology that renderer focus changed, through the
+  // platform-specific channels.
+  bool ChangeAccessibilityFocus(int acc_obj_id, int process_id, int routing_id);
 
-  // Mutator, needed since constructor does not take any arguments, and to keep
-  // instance accessor clean.
-  int SetMembers(BrowserAccessibility* browser_acc,
-                 HWND parent_hwnd,
-                 RenderWidgetHost* render_widget_host);
+  // Wrapper function, for cleaner code.
+  const WebAccessibility::OutParams& response();
 
   // NotificationObserver implementation.
   virtual void Observe(NotificationType type,
@@ -78,32 +72,24 @@ class BrowserAccessibilityManager : public NotificationObserver {
   ~BrowserAccessibilityManager();
 
  private:
-  // Member variable structure, used in instance hashmap.
-  struct UniqueMembers {
-    RenderWidgetHost* render_widget_host_;
-    HWND parent_hwnd_;
-
-    UniqueMembers(HWND parent_hwnd, RenderWidgetHost* render_widget_host)
-      : parent_hwnd_(parent_hwnd),
-        render_widget_host_(render_widget_host) {
-    }
-  };
-
-  typedef stdext::hash_map<int, UniqueMembers*> InstanceMap;
-  typedef stdext::hash_map<RenderProcessHost*, BrowserAccessibility*>
-      RenderProcessHostMap;
-
-  // Caching of the unique member variables used to handle browser accessibility
-  // requests from multiple processes.
-  InstanceMap instance_map_;
-  int instance_id_;
-
-  // Reverse mapping to track which RenderProcessHosts are active. If a
-  // RenderProcessHost is found to be terminated, it should be removed from this
-  // mapping, and the connected BrowserAccessibility ids/instances invalidated.
+  // Retrieves the BrowserAccessibility instance connected to the
+  // RenderProcessHost identified by the process/routing id pair.
+  BrowserAccessibility* GetBrowserAccessibility(int process_id, int routing_id);
+
+  // Multi-map from process id (key) to active BrowserAccessibility instances
+  // for that RenderProcessHost.
+  typedef std::multimap<int, BrowserAccessibility*> RenderProcessHostMap;
+  typedef std::pair<int, BrowserAccessibility*> MapEntry;
+
+  // Mapping to track which RenderProcessHosts ids are active. If a
+  // RenderProcessHost is found to be terminated, its id (key) should be removed
+  // from this mapping, and the connected BrowserAccessibility ids/instances
+  // invalidated.
   RenderProcessHostMap render_process_host_map_;
 
-  webkit_glue::WebAccessibility::OutParams out_params_;
+  // Structure passed by reference to hold response parameters from the
+  // renderer.
+  WebAccessibility::OutParams out_params_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserAccessibilityManager);
 };
diff --git a/chrome/browser/renderer_host/render_view_host.cc b/chrome/browser/renderer_host/render_view_host.cc
index 792b6ee..44c0023 100644
--- a/chrome/browser/renderer_host/render_view_host.cc
+++ b/chrome/browser/renderer_host/render_view_host.cc
@@ -41,6 +41,11 @@
 #include "webkit/api/public/WebFindOptions.h"
 #include "webkit/glue/autofill_form.h"
 
+#if defined(OS_WIN)
+// TODO(port): accessibility not yet implemented. See http://crbug.com/8288.
+#include "chrome/browser/browser_accessibility_manager.h"
+#endif
+
 using base::TimeDelta;
 using WebKit::WebConsoleMessage;
 using WebKit::WebFindOptions;
@@ -800,6 +805,8 @@ void RenderViewHost::OnMessageReceived(const IPC::Message& msg) {
                         OnMsgPasteFromSelectionClipboard)
     IPC_MESSAGE_HANDLER(ViewHostMsg_ExtensionPostMessage,
                         OnExtensionPostMessage)
+    IPC_MESSAGE_HANDLER(ViewHostMsg_AccessibilityFocusChange,
+                        OnAccessibilityFocusChange)
     // Have the super handle all other messages.
     IPC_MESSAGE_UNHANDLED(RenderWidgetHost::OnMessageReceived(msg))
   IPC_END_MESSAGE_MAP_EX()
@@ -1432,3 +1439,12 @@ void RenderViewHost::OnExtensionPostMessage(
   ExtensionMessageService::GetInstance(context)->
       PostMessageFromRenderer(port_id, message);
 }
+
+void RenderViewHost::OnAccessibilityFocusChange(int acc_obj_id) {
+#if defined(OS_WIN)
+  BrowserAccessibilityManager::GetInstance()->
+      ChangeAccessibilityFocus(acc_obj_id, process()->pid(), routing_id());
+#else
+  // TODO(port): accessibility not yet implemented. See http://crbug.com/8288.
+#endif
+}
diff --git a/chrome/browser/renderer_host/render_view_host.h b/chrome/browser/renderer_host/render_view_host.h
index 5c20c12..9c08f11 100644
--- a/chrome/browser/renderer_host/render_view_host.h
+++ b/chrome/browser/renderer_host/render_view_host.h
@@ -555,6 +555,7 @@ class RenderViewHost : public RenderWidgetHost {
   void OnExtensionRequest(const std::string& name, const std::string& args,
                           int request_id, bool has_callback);
   void OnExtensionPostMessage(int port_id, const std::string& message);
+  void OnAccessibilityFocusChange(int acc_obj_id);
 
   // Helper function to send a navigation message.  If a cross-site request is
   // in progress, we may be suspended while waiting for the onbeforeunload
diff --git a/chrome/browser/renderer_host/render_widget_host_view_win.cc b/chrome/browser/renderer_host/render_widget_host_view_win.cc
index 82d95f1c..22f50f7 100644
--- a/chrome/browser/renderer_host/render_widget_host_view_win.cc
+++ b/chrome/browser/renderer_host/render_widget_host_view_win.cc
@@ -13,7 +13,6 @@
 #include "base/gfx/rect.h"
 #include "base/histogram.h"
 #include "base/win_util.h"
-#include "chrome/browser/browser_accessibility.h"
 #include "chrome/browser/browser_accessibility_manager.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/browser_trial.h"
@@ -685,7 +684,7 @@ void RenderWidgetHostViewWin::OnDestroy() {
   TrackMouseLeave(false);
 #ifdef ENABLE_TRACK_HWND_DESTRUCTION
   TRACK_HWND_DESTRUCTION(m_hWnd);
-#endif //  ENABLE_TRACK_HWND_DESTRUCTION
+#endif  // ENABLE_TRACK_HWND_DESTRUCTION
 }
 
 void RenderWidgetHostViewWin::OnPaint(HDC dc) {
@@ -1194,41 +1193,23 @@ LRESULT RenderWidgetHostViewWin::OnGetObject(UINT message, WPARAM wparam,
     // If our MSAA DOM root is already created, reuse that pointer. Otherwise,
     // create a new one.
     if (!browser_accessibility_root_) {
-      CComObject<BrowserAccessibility>* accessibility = NULL;
-
-      if (!SUCCEEDED(CComObject<BrowserAccessibility>::CreateInstance(
-              &accessibility)) || !accessibility) {
-        // Return with failure.
-        return static_cast<LRESULT>(0L);
-      }
-
-      CComPtr<IAccessible> accessibility_comptr(accessibility);
-
-      // Root id is always 0, to distinguish this particular instance when
-      // mapping to the render-side IAccessible.
-      accessibility->set_iaccessible_id(0);
-
-      // Set the unique member variables of this particular process.
-      accessibility->set_instance_id(
-          BrowserAccessibilityManager::GetInstance()->
-              SetMembers(accessibility, m_hWnd, render_widget_host_));
-
-      // All is well, assign the temp instance to the class smart pointer.
-      browser_accessibility_root_.Attach(accessibility_comptr.Detach());
+      // Create a new instance of IAccessible. Root id is always 0.
+      BrowserAccessibilityManager::GetInstance()->
+          CreateAccessibilityInstance(IID_IAccessible, 0,
+                                      render_widget_host_->routing_id(),
+                                      render_widget_host_->process()->pid(),
+                                      m_hWnd, reinterpret_cast<void **>
+                                          (&browser_accessibility_root_));
 
       if (!browser_accessibility_root_) {
-        // Paranoia check. Return with failure.
+        // No valid root found, return with failure.
         NOTREACHED();
         return static_cast<LRESULT>(0L);
       }
-
-      // Notify that an instance of IAccessible was allocated for m_hWnd.
-      ::NotifyWinEvent(EVENT_OBJECT_CREATE, m_hWnd, OBJID_CLIENT,
-                       CHILDID_SELF);
     }
 
-    // Create a reference to ViewAccessibility that MSAA will marshall
-    // to the client.
+    // Create a reference to BrowserAccessibility which MSAA will marshall to
+    // the client.
     reference_result = LresultFromObject(IID_IAccessible, wparam,
         static_cast<IAccessible*>(browser_accessibility_root_));
   }
diff --git a/chrome/common/render_messages.h b/chrome/common/render_messages.h
index 2908480..e3028a2 100644
--- a/chrome/common/render_messages.h
+++ b/chrome/common/render_messages.h
@@ -509,6 +509,7 @@ struct ParamTraits<webkit_glue::WebAccessibility::InParams> {
     WriteParam(m, p.object_id);
     WriteParam(m, p.function_id);
     WriteParam(m, p.child_id);
+    WriteParam(m, p.direct_descendant);
     WriteParam(m, p.input_long1);
     WriteParam(m, p.input_long2);
   }
@@ -517,6 +518,7 @@ struct ParamTraits<webkit_glue::WebAccessibility::InParams> {
       ReadParam(m, iter, &p->object_id) &&
       ReadParam(m, iter, &p->function_id) &&
       ReadParam(m, iter, &p->child_id) &&
+      ReadParam(m, iter, &p->direct_descendant) &&
       ReadParam(m, iter, &p->input_long1) &&
       ReadParam(m, iter, &p->input_long2);
   }
@@ -528,6 +530,8 @@ struct ParamTraits<webkit_glue::WebAccessibility::InParams> {
     l->append(L", ");
     LogParam(p.child_id, l);
     l->append(L", ");
+    LogParam(p.direct_descendant, l);
+    l->append(L", ");
     LogParam(p.input_long1, l);
     l->append(L", ");
     LogParam(p.input_long2, l);
diff --git a/chrome/common/render_messages_internal.h b/chrome/common/render_messages_internal.h
index 4cf50d1..f359677 100644
--- a/chrome/common/render_messages_internal.h
+++ b/chrome/common/render_messages_internal.h
@@ -406,7 +406,7 @@ IPC_BEGIN_MESSAGES(View)
   // id to clear a specific hashmap entry, and a bool; true clears all, false
   // does not.
   IPC_MESSAGE_ROUTED2(ViewMsg_ClearAccessibilityInfo,
-                      int  /* iaccessible_id */,
+                      int  /* accessibility object id */,
                       bool /* clear_all */)
 
   // Get all savable resource links from current webpage, include main
@@ -1381,6 +1381,13 @@ IPC_BEGIN_MESSAGES(ViewHost)
   IPC_MESSAGE_ROUTED1(ViewHostMsg_ShowPopup,
                       ViewHostMsg_ShowPopup_Params)
 
+  // Sent as a result of a focus change in the renderer (if accessibility is
+  // enabled), to notify the browser side that its accessibility focus needs to
+  // change as well. Takes the id of the accessibility object that now has
+  // focus.
+  IPC_MESSAGE_ROUTED1(ViewHostMsg_AccessibilityFocusChange,
+                      int /* accessibility object id */)
+
   //---------------------------------------------------------------------------
   // Utility process host messages:
   // These are messages from the utility process to the browser.  They're here
diff --git a/chrome/renderer/render_view.cc b/chrome/renderer/render_view.cc
index dc7e284..8a311af 100644
--- a/chrome/renderer/render_view.cc
+++ b/chrome/renderer/render_view.cc
@@ -91,7 +91,6 @@
 
 using base::Time;
 using base::TimeDelta;
-using webkit_glue::WebAccessibility;
 using WebKit::WebConsoleMessage;
 using WebKit::WebDragData;
 using WebKit::WebRect;
@@ -2048,7 +2047,6 @@ void RenderView::DidDownloadImage(int id,
 void RenderView::OnDownloadImage(int id,
                                  const GURL& image_url,
                                  int image_size) {
-
   bool data_image_failed = false;
   if (image_url.SchemeIs("data")) {
     SkBitmap data_image = ImageFromDataUrl(image_url);
@@ -2765,8 +2763,10 @@ void RenderView::OnClearAccessibilityInfo(int acc_obj_id, bool clear_all) {
     // If accessibility is not activated, ignore clearing message.
     return;
   }
+
   if (!web_accessibility_manager_->ClearAccObjMap(acc_obj_id, clear_all))
     return;
+
 #else  // defined(OS_WIN)
   // TODO(port): accessibility not yet implemented
   NOTIMPLEMENTED();
@@ -3024,3 +3024,25 @@ void RenderView::DumpLoadHistograms() const {
       "Renderer.All.StartToFirstLayout", start_to_first_layout);
   }
 }
+
+void RenderView::FocusAccessibilityObject(
+    WebCore::AccessibilityObject* acc_obj) {
+#if defined(OS_WIN)
+  if (!web_accessibility_manager_.get()) {
+    web_accessibility_manager_.reset(
+        webkit_glue::WebAccessibilityManager::Create());
+  }
+
+  // Retrieve the accessibility object id of the AccessibilityObject.
+  int acc_obj_id = web_accessibility_manager_->FocusAccObj(acc_obj);
+
+  // If id is valid, alert the browser side that an accessibility focus change
+  // occurred.
+  if (acc_obj_id >= 0)
+    Send(new ViewHostMsg_AccessibilityFocusChange(routing_id_, acc_obj_id));
+
+#else  // defined(OS_WIN)
+  // TODO(port): accessibility not yet implemented
+  NOTIMPLEMENTED();
+#endif
+}
diff --git a/chrome/renderer/render_view.h b/chrome/renderer/render_view.h
index 936adae..f42b8ff 100644
--- a/chrome/renderer/render_view.h
+++ b/chrome/renderer/render_view.h
@@ -49,7 +49,6 @@ class FilePath;
 class GURL;
 class RenderThread;
 class ResourceDispatcher;
-class WebAccessibilityManager;
 class WebError;
 class WebFrame;
 class WebPluginDelegate;
@@ -307,6 +306,7 @@ class RenderView : public RenderWidget,
                                          int active_match_ordinal,
                                          const WebKit::WebRect& selection);
   virtual bool WasOpenedByUserGesture() const;
+  virtual void FocusAccessibilityObject(WebCore::AccessibilityObject* acc_obj);
   virtual void SpellCheck(const std::wstring& word, int& misspell_location,
                           int& misspell_length);
   virtual void GetAutoCorrectWord(const std::wstring& misspelled_word,
diff --git a/views/widget/widget_win.cc b/views/widget/widget_win.cc
index 4fa77a8..4dfb0ca 100644
--- a/views/widget/widget_win.cc
+++ b/views/widget/widget_win.cc
@@ -558,10 +558,6 @@ LRESULT WidgetWin::OnGetObject(UINT uMsg, WPARAM w_param, LPARAM l_param) {
         // Return with failure.
         return static_cast<LRESULT>(0L);
       }
-
-      // Notify that an instance of IAccessible was allocated for m_hWnd
-      ::NotifyWinEvent(EVENT_OBJECT_CREATE, GetNativeView(), OBJID_CLIENT,
-                       CHILDID_SELF);
     }
 
     // Create a reference to ViewAccessibility that MSAA will marshall
diff --git a/webkit/glue/chrome_client_impl.cc b/webkit/glue/chrome_client_impl.cc
index b235d35..9553e93 100644
--- a/webkit/glue/chrome_client_impl.cc
+++ b/webkit/glue/chrome_client_impl.cc
@@ -7,8 +7,11 @@
 #include "base/compiler_specific.h"
 
 MSVC_PUSH_WARNING_LEVEL(0);
+#include "AccessibilityObject.h"
+#include "AXObjectCache.h"
 #include "Console.h"
 #include "Cursor.h"
+#include "Document.h"
 #include "DocumentLoader.h"
 #include "FloatRect.h"
 #include "FileChooser.h"
@@ -16,6 +19,7 @@ MSVC_PUSH_WARNING_LEVEL(0);
 #include "FrameView.h"
 #include "HitTestResult.h"
 #include "IntRect.h"
+#include "Node.h"
 #include "Page.h"
 #include "PopupMenuChromium.h"
 #include "ScriptController.h"
@@ -29,7 +33,6 @@ MSVC_POP_WARNING();
 
 #include "webkit/glue/chrome_client_impl.h"
 
-#include "base/logging.h"
 #include "base/gfx/rect.h"
 #include "googleurl/src/gurl.h"
 #include "webkit/api/public/WebInputEvent.h"
@@ -141,6 +144,28 @@ void ChromeClientImpl::focus() {
   WebViewDelegate* delegate = webview_->delegate();
   if (delegate)
     delegate->Focus(webview_);
+
+  // If accessibility is enabled, we should notify assistive technology that the
+  // active AccessibilityObject changed.
+  WebCore::Document* doc = webview_->GetFocusedWebCoreFrame()->document();
+
+  if (doc && doc->axObjectCache()->accessibilityEnabled()) {
+    WebCore::Node* focused_node = webview_->GetFocusedNode();
+
+    if (!focused_node) {
+      // Could not retrieve focused Node.
+      return;
+    }
+
+    // Retrieve the focused AccessibilityObject.
+    WebCore::AccessibilityObject* focused_acc_obj =
+        doc->axObjectCache()->getOrCreate(focused_node->renderer());
+
+    // Alert assistive technology that focus changed.
+    if (focused_acc_obj) {
+      delegate->FocusAccessibilityObject(focused_acc_obj);
+    }
+  }
 }
 
 void ChromeClientImpl::unfocus() {
@@ -201,7 +226,8 @@ static inline bool CurrentEventShouldCauseBackgroundTab(
   if (input_event->type != WebInputEvent::MouseUp)
     return false;
 
-  const WebMouseEvent* mouse_event = static_cast<const WebMouseEvent*>(input_event);
+  const WebMouseEvent* mouse_event =
+      static_cast<const WebMouseEvent*>(input_event);
   return (mouse_event->button == WebMouseEvent::ButtonMiddle);
 }
 
@@ -294,7 +320,8 @@ void ChromeClientImpl::addMessageToConsole(WebCore::MessageSource source,
   }
   WebDevToolsAgentImpl* devtools_agent = webview_->GetWebDevToolsAgentImpl();
   if (devtools_agent) {
-    devtools_agent->AddMessageToConsole(source, level, message, line_no, source_id);
+    devtools_agent->AddMessageToConsole(source, level, message, line_no,
+                                        source_id);
   }
 }
 
diff --git a/webkit/glue/chrome_client_impl.h b/webkit/glue/chrome_client_impl.h
index e372f7c..3a3fdc5 100644
--- a/webkit/glue/chrome_client_impl.h
+++ b/webkit/glue/chrome_client_impl.h
@@ -24,7 +24,7 @@ struct WindowFeatures;
 // Handles window-level notifications from WebCore on behalf of a WebView.
 class ChromeClientImpl : public WebCore::ChromeClientChromium {
  public:
-  ChromeClientImpl(WebViewImpl* webview);
+  explicit ChromeClientImpl(WebViewImpl* webview);
   virtual ~ChromeClientImpl();
 
   WebViewImpl* webview() const { return webview_; }
@@ -67,7 +67,8 @@ class ChromeClientImpl : public WebCore::ChromeClientChromium {
   virtual void setResizable(bool);
 
   virtual void addMessageToConsole(WebCore::MessageSource source,
-                                   WebCore::MessageLevel level, const WebCore::String& message,
+                                   WebCore::MessageLevel level,
+                                   const WebCore::String& message,
                                    unsigned int lineNumber,
                                    const WebCore::String& sourceID);
 
diff --git a/webkit/glue/glue_accessibility_object.cc b/webkit/glue/glue_accessibility_object.cc
index 17a693e..8c056eb 100644
--- a/webkit/glue/glue_accessibility_object.cc
+++ b/webkit/glue/glue_accessibility_object.cc
@@ -134,7 +134,7 @@ GlueAccessibilityObject* GlueAccessibilityObject::Navigate(
 GlueAccessibilityObject* GlueAccessibilityObject::GetChild(int child_id) {
   AccessibilityObject* child_obj;
   if (!GetAccessibilityObjectForChild(child_id, child_obj))
-    return false;
+    return NULL;
 
   // TODO(klink): simple object child?
   ToWrapper(child_obj)->ref();
diff --git a/webkit/glue/glue_accessibility_object.h b/webkit/glue/glue_accessibility_object.h
index 137a7e3..f94f9a1 100644
--- a/webkit/glue/glue_accessibility_object.h
+++ b/webkit/glue/glue_accessibility_object.h
@@ -27,6 +27,8 @@ class GlueAccessibilityObject : public WebCore::AccessibilityObjectWrapper {
  public:
   static GlueAccessibilityObject* CreateInstance(WebCore::AccessibilityObject*);
 
+  virtual ~GlueAccessibilityObject() {}
+
   // Performs the default action on a given object.
   bool DoDefaultAction(int child_id);
 
@@ -91,7 +93,6 @@ class GlueAccessibilityObject : public WebCore::AccessibilityObjectWrapper {
 
  protected:
   explicit GlueAccessibilityObject(WebCore::AccessibilityObject*);
-  virtual ~GlueAccessibilityObject() {}
 
   // Helper functions.
   WebCore::String name() const;
diff --git a/webkit/glue/webaccessibility.h b/webkit/glue/webaccessibility.h
index 538e612..250c665 100644
--- a/webkit/glue/webaccessibility.h
+++ b/webkit/glue/webaccessibility.h
@@ -117,6 +117,10 @@ class WebAccessibility {
     // Id of accessible child, whose information is being requested.
     int child_id;
 
+    // Indicates if the |child_id| refers to a direct child of the active
+    // accessibility object (true) or not (false).
+    bool direct_descendant;
+
     // LONG input parameters, used differently depending on the function called.
     long input_long1;
     long input_long2;
diff --git a/webkit/glue/webaccessibilitymanager.h b/webkit/glue/webaccessibilitymanager.h
index cebe94c..c94fbb9 100644
--- a/webkit/glue/webaccessibilitymanager.h
+++ b/webkit/glue/webaccessibilitymanager.h
@@ -7,6 +7,10 @@
 
 #include "webkit/glue/webaccessibility.h"
 
+namespace WebCore {
+class AccessibilityObject;
+}
+
 class WebView;
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -24,6 +28,7 @@ class WebAccessibilityManager {
   WebAccessibilityManager() {}
   virtual ~WebAccessibilityManager() {}
 
+  // Creates a new instance of WebAccessibilityManager.
   static WebAccessibilityManager* Create();
 
   // Retrieves the accessibility information as requested in in_params, by
@@ -39,13 +44,17 @@ class WebAccessibilityManager {
   // false otherwise.
   virtual bool ClearAccObjMap(int acc_obj_id, bool clear_all) = 0;
 
+  // Retrieves the id of the input AccessibilityObject, due to a focus event.
+  // Returns an id greater than or equal to 0 if successful, -1 otherwise.
+  virtual int FocusAccObj(WebCore::AccessibilityObject* acc_obj) = 0;
+
+ private:
   // Retrieves the RenderObject associated with this WebView, and uses it to
   // initialize the root of the GlueAccessibilityObject tree with the
   // associated accessibility information. Returns true if successful, false
   // otherwise.
   virtual bool InitAccObjRoot(WebView* view) = 0;
 
- private:
   DISALLOW_COPY_AND_ASSIGN(WebAccessibilityManager);
 };
 
diff --git a/webkit/glue/webaccessibilitymanager_impl.cc b/webkit/glue/webaccessibilitymanager_impl.cc
index 57ac0c7..f765127 100644
--- a/webkit/glue/webaccessibilitymanager_impl.cc
+++ b/webkit/glue/webaccessibilitymanager_impl.cc
@@ -34,7 +34,13 @@ WebAccessibilityManager* WebAccessibilityManager::Create() {
 
 // class WebAccessibilityManagerImpl
 WebAccessibilityManagerImpl::WebAccessibilityManagerImpl()
-    : root_(new GlueAccessibilityObjectRoot) {
+    : root_(new GlueAccessibilityObjectRoot),
+      acc_obj_id_(0) {
+}
+
+WebAccessibilityManagerImpl::~WebAccessibilityManagerImpl() {
+  int_to_glue_acc_obj_map_.clear();
+  acc_obj_to_int_map_.clear();
 }
 
 bool WebAccessibilityManagerImpl::GetAccObjInfo(WebView* view,
@@ -45,18 +51,28 @@ bool WebAccessibilityManagerImpl::GetAccObjInfo(WebView* view,
     return false;
   }
 
-  // Find GlueAccessibilityObject requested by [in_params.object_id].
-  IntToAccObjMap::iterator it =
-      int_to_acc_obj_map_.find(in_params.object_id);
-  if (it == int_to_acc_obj_map_.end() || !it->second) {
+  // Function input parameters.
+  int object_id = in_params.object_id;
+  int child_id = in_params.child_id;
+
+  if (!in_params.direct_descendant) {
+    // Object is not a direct child, re-map the input parameters accordingly.
+    // The object to be retrieved is referred to by the |in_params.child_id|, as
+    // a result of e.g. a focus event. The local |child_id| is set to 0, to
+    // indicate that any function call should refer to the object itself.
+    object_id = in_params.child_id;
+    child_id = 0;
+  }
+
+  // Find GlueAccessibilityObject requested by |object_id|.
+  IntToGlueAccObjMap::iterator it =
+      int_to_glue_acc_obj_map_.find(object_id);
+  if (it == int_to_glue_acc_obj_map_.end() || !it->second) {
     // Map did not contain a valid instance of the data requested.
     return false;
   }
   RefPtr<GlueAccessibilityObject> active_acc_obj = it->second;
 
-  // Function input parameters.
-  int child_id = in_params.child_id;
-
   // Temp paramters for holding output information.
   RefPtr<GlueAccessibilityObject> out_acc_obj = NULL;
   WebCore::String out_string;
@@ -156,7 +172,8 @@ bool WebAccessibilityManagerImpl::GetAccObjInfo(WebView* view,
     out_params->output_string = StringToString16(out_string);
 
   if (out_acc_obj) {
-    AccObjToIntMap::iterator it = acc_obj_to_int_map_.find(out_acc_obj.get());
+    AccObjToIntMap::iterator it =
+        acc_obj_to_int_map_.find(out_acc_obj->accessibilityObject());
 
     if (it != acc_obj_to_int_map_.end()) {
       // Data already present in map, return previously assigned id.
@@ -164,8 +181,8 @@ bool WebAccessibilityManagerImpl::GetAccObjInfo(WebView* view,
       out_params->output_long1 = -1;
     } else {
       // Insert new GlueAccessibilityObject in hashmaps.
-      int_to_acc_obj_map_[acc_obj_id_] = out_acc_obj.get();
-      acc_obj_to_int_map_[out_acc_obj.get()] = acc_obj_id_;
+      int_to_glue_acc_obj_map_[acc_obj_id_] = out_acc_obj.get();
+      acc_obj_to_int_map_[out_acc_obj->accessibilityObject()] = acc_obj_id_;
       out_params->object_id = acc_obj_id_++;
       out_params->output_long1 = -1;
     }
@@ -175,9 +192,6 @@ bool WebAccessibilityManagerImpl::GetAccObjInfo(WebView* view,
 }
 
 bool WebAccessibilityManagerImpl::InitAccObjRoot(WebView* view) {
-  // Root id is always 0.
-  acc_obj_id_ = 0;
-
   // Enable accessibility and retrieve Document.
   WebCore::AXObjectCache::enableAccessibility();
   WebFrameImpl* main_frame_impl =
@@ -199,8 +213,9 @@ bool WebAccessibilityManagerImpl::InitAccObjRoot(WebView* view) {
         axObjectCache()->getOrCreate(doc->renderer()));
   }
   // Insert root in hashmaps.
-  int_to_acc_obj_map_[acc_obj_id_] = root_->acc_obj_root_.get();
-  acc_obj_to_int_map_[root_->acc_obj_root_.get()] = acc_obj_id_++;
+  int_to_glue_acc_obj_map_[acc_obj_id_] = root_->acc_obj_root_.get();
+  acc_obj_to_int_map_[root_->acc_obj_root_->accessibilityObject()] =
+      acc_obj_id_++;
 
   return true;
 }
@@ -209,27 +224,28 @@ bool WebAccessibilityManagerImpl::ClearAccObjMap(int acc_obj_id,
                                                  bool clear_all) {
   if (clear_all) {
     // Clear maps and invalidate root.
-    int_to_acc_obj_map_.clear();
+    int_to_glue_acc_obj_map_.clear();
     acc_obj_to_int_map_.clear();
     root_->acc_obj_root_ = 0;
     return true;
   }
 
-  IntToAccObjMap::iterator it = int_to_acc_obj_map_.find(acc_obj_id);
+  IntToGlueAccObjMap::iterator it = int_to_glue_acc_obj_map_.find(acc_obj_id);
 
-  if (it == int_to_acc_obj_map_.end()) {
+  if (it == int_to_glue_acc_obj_map_.end()) {
     // Element not found.
     return false;
   }
 
   if (it->second) {
     // Erase element from reverse hashmap.
-    AccObjToIntMap::iterator it2 = acc_obj_to_int_map_.find(it->second);
+    AccObjToIntMap::iterator it2 =
+        acc_obj_to_int_map_.find(it->second->accessibilityObject());
 
     if (it2 != acc_obj_to_int_map_.end())
       acc_obj_to_int_map_.erase(it2);
   }
-  int_to_acc_obj_map_.erase(it);
+  int_to_glue_acc_obj_map_.erase(it);
 
   if (acc_obj_id == 0) {
     // Invalidate root.
@@ -238,4 +254,25 @@ bool WebAccessibilityManagerImpl::ClearAccObjMap(int acc_obj_id,
   return true;
 }
 
+int WebAccessibilityManagerImpl::FocusAccObj(
+    WebCore::AccessibilityObject* acc_obj) {
+  if (!acc_obj) {
+    // Return with failure.
+    return -1;
+  }
+
+  AccObjToIntMap::iterator it = acc_obj_to_int_map_.find(acc_obj);
+
+  if (it != acc_obj_to_int_map_.end())
+    return it->second;
+
+  // Insert new accessibility object in hashmaps and return its newly
+  // assigned accessibility object id.
+  int_to_glue_acc_obj_map_[acc_obj_id_] =
+      GlueAccessibilityObject::CreateInstance(acc_obj);
+  acc_obj_to_int_map_[acc_obj] = acc_obj_id_;
+
+  return acc_obj_id_++;
+}
+
 }  // namespace webkit_glue
diff --git a/webkit/glue/webaccessibilitymanager_impl.h b/webkit/glue/webaccessibilitymanager_impl.h
index fe28e4e..1bc0607 100644
--- a/webkit/glue/webaccessibilitymanager_impl.h
+++ b/webkit/glue/webaccessibilitymanager_impl.h
@@ -10,10 +10,6 @@
 
 class GlueAccessibilityObject;
 
-namespace webkit_glue {
-typedef base::hash_map<int, GlueAccessibilityObject*> IntToAccObjMap;
-typedef base::hash_map<GlueAccessibilityObject*, int> AccObjToIntMap;
-
 ////////////////////////////////////////////////////////////////////////////////
 //
 // WebAccessibilityManagerImpl
@@ -24,21 +20,23 @@ typedef base::hash_map<GlueAccessibilityObject*, int> AccObjToIntMap;
 // the requested information from the active AccessibilityObject, through the
 // GlueAccessibilityObject.
 ////////////////////////////////////////////////////////////////////////////////
+
+namespace webkit_glue {
+
 class WebAccessibilityManagerImpl : public WebAccessibilityManager {
  public:
   // From WebAccessibilityManager.
   bool GetAccObjInfo(WebView* view, const WebAccessibility::InParams& in_params,
                      WebAccessibility::OutParams* out_params);
-
-  // From WebAccessibilityManager.
   bool ClearAccObjMap(int acc_obj_id, bool clear_all);
+  int FocusAccObj(WebCore::AccessibilityObject* acc_obj);
 
  protected:
   // Needed so WebAccessibilityManager::Create can call our constructor.
   friend class WebAccessibilityManager;
 
   WebAccessibilityManagerImpl();
-  ~WebAccessibilityManagerImpl() {}
+  ~WebAccessibilityManagerImpl();
 
  private:
   // From WebAccessibilityManager.
@@ -49,17 +47,21 @@ class WebAccessibilityManagerImpl : public WebAccessibilityManager {
   struct GlueAccessibilityObjectRoot;
   GlueAccessibilityObjectRoot* root_;
 
+  typedef base::hash_map<int, GlueAccessibilityObject*> IntToGlueAccObjMap;
+  typedef base::hash_map<WebCore::AccessibilityObject*, int> AccObjToIntMap;
+
   // Hashmap for cashing of elements in use by the AT, mapping id (int) to a
   // GlueAccessibilityObject pointer.
-  IntToAccObjMap int_to_acc_obj_map_;
+  IntToGlueAccObjMap int_to_glue_acc_obj_map_;
   // Hashmap for cashing of elements in use by the AT, mapping a
-  // GlueAccessibilityObject pointer to its id (int). Needed for reverse lookup,
+  // AccessibilityObject pointer to its id (int). Needed for reverse lookup,
   // to ensure unnecessary duplicate entries are not created in the
-  // IntToAccObjMap (above).
+  // IntToGlueAccObjMap (above) and for focus changes in WebKit.
   AccObjToIntMap acc_obj_to_int_map_;
 
-  // Unique identifier for retrieving a GlueAccessibilityObject from the page's
-  // hashmaps.
+  // Unique identifier for retrieving an accessibility object from the page's
+  // hashmaps. Id is always 0 for the root of the accessibility object
+  // hierarchy (on a per-renderer process basis).
   int acc_obj_id_;
 
   DISALLOW_COPY_AND_ASSIGN(WebAccessibilityManagerImpl);
diff --git a/webkit/glue/webview_delegate.h b/webkit/glue/webview_delegate.h
index 525f745..7d503ad 100644
--- a/webkit/glue/webview_delegate.h
+++ b/webkit/glue/webview_delegate.h
@@ -37,6 +37,10 @@ namespace webkit_glue {
 class WebMediaPlayerDelegate;
 }
 
+namespace WebCore {
+class AccessibilityObject;
+}
+
 namespace WebKit {
 class WebDragData;
 class WebWorker;
@@ -169,6 +173,13 @@ class WebViewDelegate : virtual public WebWidgetDelegate {
     return true;
   }
 
+  // Called by ChromeClientImpl::focus() if accessibility on the renderer side
+  // is enabled, and a focus change has occurred. Will retrieve the id of the
+  // input AccessibilityObject and send it through IPC for handling on the
+  // browser side.
+  virtual void FocusAccessibilityObject(WebCore::AccessibilityObject* acc_obj) {
+  }
+
   // FrameLoaderClient -------------------------------------------------------
 
   // Notifies the delegate that a load has begun.
diff --git a/webkit/glue/webview_impl.h b/webkit/glue/webview_impl.h
index ae26890..caac1c8 100644
--- a/webkit/glue/webview_impl.h
+++ b/webkit/glue/webview_impl.h
@@ -138,6 +138,9 @@ class WebViewImpl : public WebView, public base::RefCounted<WebViewImpl> {
 
   WebCore::Frame* GetFocusedWebCoreFrame();
 
+  // Returns the currently focused Node or NULL if no node has focus.
+  WebCore::Node* GetFocusedNode();
+
   static WebViewImpl* FromPage(WebCore::Page* page);
 
   WebViewDelegate* delegate() {
@@ -285,9 +288,6 @@ class WebViewImpl : public WebView, public base::RefCounted<WebViewImpl> {
   WebCore::HitTestResult HitTestResultForWindowPos(
       const WebCore::IntPoint& pos);
 
-  // Returns the currently focused Node or NULL if no node has focus.
-  WebCore::Node* GetFocusedNode();
-
   // ImageResourceFetchers schedule via DownloadImage.
   std::set<ImageResourceFetcher*> image_fetchers_;