Revert 135593 - Add initial GTK web accessibility framework (new with valgrind fix).

This is the same as http://codereview.chromium.org/9839069/ which was
landed but reverted due to a valgrind failure in content_unittests.

The valgrind failure was because browser_accessibility_manager_unittest.cc
is constructing its own subclass of BrowserAccessibility (for testing),
but BrowserAccessibilityManagerGtk was assuming that any BrowserAccessibility
could be static_casted to a BrowserAccessibilityGtk. I fixed this by
making ToBrowserAccessibilityGtk() a virtual method with a default impl that
returns NULL.

Original change:

This enables Linux desktop assistive technology such as the Orca screen 
reader to access the web contents. Builds on the same accessibility stack 
used by Mac & Windows already. 

This change works with Orca now, but it's minimal: all that works is getting 
the correct feedback when you tab through focusable links and controls in 
a webpage. Future changes will add the rest of the support. 

BUG=24585
TEST=Run Chrome on desktop Linux with Orca turned on, tab through links. 
TBR=darin,sky
Review URL: https://chromiumcodereview.appspot.com/10381010

TBR=dmazzoni@chromium.org
Review URL: https://chromiumcodereview.appspot.com/10379029

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@135595 0039d316-1c4b-4281-b951-d872f2087c98

24 files changed, 92 insertions, 783 deletions

diff --git a/content/browser/accessibility/browser_accessibility.cc b/content/browser/accessibility/browser_accessibility.cc
index 93e8f9c..4f81569 100644
--- a/content/browser/accessibility/browser_accessibility.cc
+++ b/content/browser/accessibility/browser_accessibility.cc
@@ -15,11 +15,9 @@ typedef WebAccessibility::FloatAttribute FloatAttribute;
 typedef WebAccessibility::IntAttribute IntAttribute;
 typedef WebAccessibility::StringAttribute StringAttribute;
 
-#if !defined(OS_MACOSX) && \
-    !(defined(OS_WIN) && !defined(USE_AURA)) && \
-    !defined(TOOLKIT_GTK)
-// We have subclassess of BrowserAccessibility on Mac, Linux/GTK,
-// and non-Aura Win. For any other platform, instantiate the base class.
+#if (defined(OS_POSIX) && !defined(OS_MACOSX)) || defined(USE_AURA)
+// There's no OS-specific implementation of BrowserAccessibilityManager
+// on Unix, so just instantiate the base class.
 // static
 BrowserAccessibility* BrowserAccessibility::Create() {
   return new BrowserAccessibility();
@@ -204,20 +202,6 @@ void BrowserAccessibility::NativeReleaseReference() {
   delete this;
 }
 
-#if defined(OS_MACOSX)
-BrowserAccessibilityMac* BrowserAccessibility::ToBrowserAccessibilityMac() {
-  return NULL;
-}
-#elif defined(OS_WIN)
-BrowserAccessibilityWin* BrowserAccessibility::ToBrowserAccessibilityWin() {
-  return NULL;
-}
-#elif defined(TOOLKIT_GTK)
-BrowserAccessibilityGtk* BrowserAccessibility::ToBrowserAccessibilityGtk() {
-  return NULL;
-}
-#endif
-
 bool BrowserAccessibility::GetBoolAttribute(
     BoolAttribute attribute, bool* value) const {
   BoolAttrMap::const_iterator iter = bool_attributes_.find(attribute);
diff --git a/content/browser/accessibility/browser_accessibility.h b/content/browser/accessibility/browser_accessibility.h
index c789c19..0fbb3eb 100644
--- a/content/browser/accessibility/browser_accessibility.h
+++ b/content/browser/accessibility/browser_accessibility.h
@@ -16,12 +16,10 @@
 #include "webkit/glue/webaccessibility.h"
 
 class BrowserAccessibilityManager;
-#if defined(OS_MACOSX)
-class BrowserAccessibilityMac;
+#if defined(OS_MACOSX) && __OBJC__
+@class BrowserAccessibilityCocoa;
 #elif defined(OS_WIN)
 class BrowserAccessibilityWin;
-#elif defined(TOOLKIT_GTK)
-class BrowserAccessibilityGtk;
 #endif
 
 using webkit_glue::WebAccessibility;
@@ -189,12 +187,10 @@ class CONTENT_EXPORT BrowserAccessibility {
   bool instance_active() const { return instance_active_; }
   int32 ref_count() const { return ref_count_; }
 
-#if defined(OS_MACOSX)
-  virtual BrowserAccessibilityMac* ToBrowserAccessibilityMac();
+#if defined(OS_MACOSX) && __OBJC__
+  BrowserAccessibilityCocoa* toBrowserAccessibilityCocoa();
 #elif defined(OS_WIN)
-  virtual BrowserAccessibilityWin* ToBrowserAccessibilityWin();
-#elif defined(TOOLKIT_GTK)
-  virtual BrowserAccessibilityGtk* ToBrowserAccessibilityGtk();
+  BrowserAccessibilityWin* toBrowserAccessibilityWin();
 #endif
 
   // Retrieve the value of a bool attribute from the bool attribute
diff --git a/content/browser/accessibility/browser_accessibility_cocoa.mm b/content/browser/accessibility/browser_accessibility_cocoa.mm
index 3a434ff..b282cad 100644
--- a/content/browser/accessibility/browser_accessibility_cocoa.mm
+++ b/content/browser/accessibility/browser_accessibility_cocoa.mm
@@ -12,7 +12,6 @@
 #include "base/string16.h"
 #include "base/sys_string_conversions.h"
 #include "base/utf_string_conversions.h"
-#include "content/browser/accessibility/browser_accessibility_mac.h"
 #include "content/browser/accessibility/browser_accessibility_manager.h"
 #include "content/public/common/content_client.h"
 #include "grit/webkit_strings.h"
@@ -344,8 +343,7 @@ NSDictionary* attributeToMethodNameMap = nil;
          index < browserAccessibility_->child_count();
          ++index) {
       BrowserAccessibilityCocoa* child =
-          browserAccessibility_->GetChild(index)->
-              ToBrowserAccessibilityMac()->native_view();
+          browserAccessibility_->GetChild(index)->toBrowserAccessibilityCocoa();
       if ([child isIgnored])
         [children_ addObjectsFromArray:[child children]];
       else
@@ -364,7 +362,7 @@ NSDictionary* attributeToMethodNameMap = nil;
       // a DCHECK in the future.
       if (child) {
         BrowserAccessibilityCocoa* child_cocoa =
-            child->ToBrowserAccessibilityMac()->native_view();
+            child->toBrowserAccessibilityCocoa();
         [children_ addObject:child_cocoa];
       }
     }
@@ -375,9 +373,9 @@ NSDictionary* attributeToMethodNameMap = nil;
 - (void)childrenChanged {
   if (![self isIgnored]) {
     children_.reset();
-  } else if (browserAccessibility_->parent()) {
-    [browserAccessibility_->parent()->ToBrowserAccessibilityMac()->native_view()
-         childrenChanged];
+  } else {
+    [browserAccessibility_->parent()->toBrowserAccessibilityCocoa()
+       childrenChanged];
   }
 }
 
@@ -490,8 +488,7 @@ NSDictionary* attributeToMethodNameMap = nil;
   // A nil parent means we're the root.
   if (browserAccessibility_->parent()) {
     return NSAccessibilityUnignoredAncestor(
-        browserAccessibility_->parent()->ToBrowserAccessibilityMac()->
-            native_view());
+        browserAccessibility_->parent()->toBrowserAccessibilityCocoa());
   } else {
     // Hook back up to RenderWidgetHostViewCocoa.
     return browserAccessibility_->manager()->GetParentView();
@@ -635,7 +632,7 @@ NSDictionary* attributeToMethodNameMap = nil;
     BrowserAccessibility* titleElement =
         browserAccessibility_->manager()->GetFromRendererID(titleElementId);
     if (titleElement)
-      return titleElement->ToBrowserAccessibilityMac()->native_view();
+      return titleElement->toBrowserAccessibilityCocoa();
   }
   return nil;
 }
diff --git a/content/browser/accessibility/browser_accessibility_gtk.cc b/content/browser/accessibility/browser_accessibility_gtk.cc
deleted file mode 100644
index 7a3e3f7..0000000
--- a/content/browser/accessibility/browser_accessibility_gtk.cc
+++ /dev/null
@@ -1,343 +0,0 @@
-// 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_gtk.h"
-
-#include "base/utf_string_conversions.h"
-#include "content/browser/accessibility/browser_accessibility_manager_gtk.h"
-#include "content/common/accessibility_messages.h"
-
-#include <gtk/gtk.h>
-
-using webkit_glue::WebAccessibility;
-
-// The maximum length of an autogenerated unique type name string,
-// generated from the 16-bit interface mask from an AtkObject.
-// 30 is enough for the prefix "WAIType" + 5 hex chars (max) */
-static const int kWAITypeNameLen = 30;
-
-static gpointer browser_accessibility_parent_class = NULL;
-
-static BrowserAccessibilityGtk* ToBrowserAccessibilityGtk(
-    BrowserAccessibilityAtk* atk_object) {
-  if (!atk_object)
-    return NULL;
-
-  return atk_object->m_object;
-}
-
-static BrowserAccessibilityGtk* ToBrowserAccessibilityGtk(
-    AtkObject* atk_object) {
-  if (!IS_BROWSER_ACCESSIBILITY(atk_object))
-    return NULL;
-
-  return ToBrowserAccessibilityGtk(BROWSER_ACCESSIBILITY(atk_object));
-}
-
-static const gchar* browser_accessibility_get_name(AtkObject* atk_object) {
-  BrowserAccessibilityGtk* obj = ToBrowserAccessibilityGtk(atk_object);
-  return obj->atk_acc_name().c_str();
-}
-
-static const gchar* browser_accessibility_get_description(
-    AtkObject* atk_object) {
-  BrowserAccessibilityGtk* obj = ToBrowserAccessibilityGtk(atk_object);
-  string16 description;
-  obj->GetStringAttribute(WebAccessibility::ATTR_DESCRIPTION, &description);
-  return UTF16ToUTF8(description).c_str();
-}
-
-static AtkObject* browser_accessibility_get_parent(AtkObject* atk_object) {
-  BrowserAccessibilityGtk* obj = ToBrowserAccessibilityGtk(atk_object);
-  if (obj->parent())
-    return obj->parent()->ToBrowserAccessibilityGtk()->GetAtkObject();
-  else
-    return gtk_widget_get_accessible(obj->manager()->GetParentView());
-}
-
-static gint browser_accessibility_get_n_children(AtkObject* atk_object) {
-  BrowserAccessibilityGtk* obj = ToBrowserAccessibilityGtk(atk_object);
-  return obj->children().size();
-}
-
-static AtkObject* browser_accessibility_ref_child(
-    AtkObject* atk_object, gint index) {
-  BrowserAccessibilityGtk* obj = ToBrowserAccessibilityGtk(atk_object);
-  AtkObject* result =
-      obj->children()[index]->ToBrowserAccessibilityGtk()->GetAtkObject();
-  g_object_ref(result);
-  return result;
-}
-
-static gint browser_accessibility_get_index_in_parent(AtkObject* atk_object) {
-  BrowserAccessibilityGtk* obj = ToBrowserAccessibilityGtk(atk_object);
-  return obj->index_in_parent();
-}
-
-static AtkAttributeSet* browser_accessibility_get_attributes(
-    AtkObject* atk_object) {
-  return NULL;
-}
-
-static AtkRole browser_accessibility_get_role(AtkObject* atk_object) {
-  BrowserAccessibilityGtk* obj = ToBrowserAccessibilityGtk(atk_object);
-  return obj->atk_role();
-}
-
-static AtkStateSet* browser_accessibility_ref_state_set(AtkObject* atk_object) {
-  BrowserAccessibilityGtk* obj = ToBrowserAccessibilityGtk(atk_object);
-  AtkStateSet* state_set =
-      ATK_OBJECT_CLASS(browser_accessibility_parent_class)->
-          ref_state_set(atk_object);
-  int32 state = obj->state();
-
-  if ((state >> WebAccessibility::STATE_FOCUSABLE) & 1)
-    atk_state_set_add_state(state_set, ATK_STATE_FOCUSABLE);
-  if (obj->manager()->GetFocus(NULL) == obj)
-    atk_state_set_add_state(state_set, ATK_STATE_FOCUSED);
-
-  return state_set;
-}
-
-static AtkRelationSet* browser_accessibility_ref_relation_set(
-    AtkObject* atk_object) {
-  AtkRelationSet* relation_set =
-      ATK_OBJECT_CLASS(browser_accessibility_parent_class)
-          ->ref_relation_set(atk_object);
-  return relation_set;
-}
-
-static void browser_accessibility_init(AtkObject* atk_object, gpointer data) {
-  if (ATK_OBJECT_CLASS(browser_accessibility_parent_class)->initialize) {
-    ATK_OBJECT_CLASS(browser_accessibility_parent_class)->initialize(
-        atk_object, data);
-  }
-
-  BROWSER_ACCESSIBILITY(atk_object)->m_object =
-      reinterpret_cast<BrowserAccessibilityGtk*>(data);
-}
-
-static void browser_accessibility_finalize(GObject* atk_object) {
-  G_OBJECT_CLASS(browser_accessibility_parent_class)->finalize(atk_object);
-}
-
-static void browser_accessibility_class_init(AtkObjectClass* klass) {
-  GObjectClass* gobject_class = G_OBJECT_CLASS(klass);
-  browser_accessibility_parent_class = g_type_class_peek_parent(klass);
-
-  gobject_class->finalize = browser_accessibility_finalize;
-  klass->initialize = browser_accessibility_init;
-  klass->get_name = browser_accessibility_get_name;
-  klass->get_description = browser_accessibility_get_description;
-  klass->get_parent = browser_accessibility_get_parent;
-  klass->get_n_children = browser_accessibility_get_n_children;
-  klass->ref_child = browser_accessibility_ref_child;
-  klass->get_role = browser_accessibility_get_role;
-  klass->ref_state_set = browser_accessibility_ref_state_set;
-  klass->get_index_in_parent = browser_accessibility_get_index_in_parent;
-  klass->get_attributes = browser_accessibility_get_attributes;
-  klass->ref_relation_set = browser_accessibility_ref_relation_set;
-}
-
-GType browser_accessibility_get_type() {
-  static volatile gsize type_volatile = 0;
-
-  if (g_once_init_enter(&type_volatile)) {
-    static const GTypeInfo tinfo = {
-      sizeof(BrowserAccessibilityAtkClass),
-      (GBaseInitFunc) 0,
-      (GBaseFinalizeFunc) 0,
-      (GClassInitFunc) browser_accessibility_class_init,
-      (GClassFinalizeFunc) 0,
-      0, /* class data */
-      sizeof(BrowserAccessibilityAtk), /* instance size */
-      0, /* nb preallocs */
-      (GInstanceInitFunc) 0,
-      0 /* value table */
-    };
-
-    GType type = g_type_register_static(
-        ATK_TYPE_OBJECT, "BrowserAccessibility", &tinfo, GTypeFlags(0));
-    g_once_init_leave(&type_volatile, type);
-  }
-
-  return type_volatile;
-}
-
-static guint16 GetInterfaceMaskFromObject(BrowserAccessibilityGtk* obj) {
-  return 0;
-}
-
-static const char* GetUniqueAccessibilityTypeName(guint16 interface_mask)
-{
-  static char name[kWAITypeNameLen + 1];
-
-  sprintf(name, "WAIType%x", interface_mask);
-  name[kWAITypeNameLen] = '\0';
-
-  return name;
-}
-
-static const GInterfaceInfo AtkInterfacesInitFunctions[] = {
-};
-
-enum WAIType {
-  WAI_ACTION,
-  WAI_SELECTION,
-  WAI_EDITABLE_TEXT,
-  WAI_TEXT,
-  WAI_COMPONENT,
-  WAI_IMAGE,
-  WAI_TABLE,
-  WAI_HYPERTEXT,
-  WAI_HYPERLINK,
-  WAI_DOCUMENT,
-  WAI_VALUE,
-};
-
-static GType GetAtkInterfaceTypeFromWAIType(WAIType type) {
-  switch (type) {
-    case WAI_ACTION:
-      return ATK_TYPE_ACTION;
-    case WAI_SELECTION:
-      return ATK_TYPE_SELECTION;
-    case WAI_EDITABLE_TEXT:
-      return ATK_TYPE_EDITABLE_TEXT;
-    case WAI_TEXT:
-      return ATK_TYPE_TEXT;
-    case WAI_COMPONENT:
-      return ATK_TYPE_COMPONENT;
-    case WAI_IMAGE:
-      return ATK_TYPE_IMAGE;
-    case WAI_TABLE:
-      return ATK_TYPE_TABLE;
-    case WAI_HYPERTEXT:
-      return ATK_TYPE_HYPERTEXT;
-    case WAI_HYPERLINK:
-      return ATK_TYPE_HYPERLINK_IMPL;
-    case WAI_DOCUMENT:
-      return ATK_TYPE_DOCUMENT;
-    case WAI_VALUE:
-      return ATK_TYPE_VALUE;
-  }
-
-  return G_TYPE_INVALID;
-}
-
-static GType GetAccessibilityTypeFromObject(BrowserAccessibilityGtk* obj) {
-  static const GTypeInfo type_info = {
-    sizeof(BrowserAccessibilityAtkClass),
-    (GBaseInitFunc) 0,
-    (GBaseFinalizeFunc) 0,
-    (GClassInitFunc) 0,
-    (GClassFinalizeFunc) 0,
-    0, /* class data */
-    sizeof(BrowserAccessibilityAtk), /* instance size */
-    0, /* nb preallocs */
-    (GInstanceInitFunc) 0,
-    0 /* value table */
-  };
-
-  guint16 interface_mask = GetInterfaceMaskFromObject(obj);
-  const char* atk_type_name = GetUniqueAccessibilityTypeName(interface_mask);
-  GType type = g_type_from_name(atk_type_name);
-  if (type)
-    return type;
-
-  type = g_type_register_static(BROWSER_ACCESSIBILITY_TYPE,
-                                atk_type_name,
-                                &type_info,
-                                GTypeFlags(0));
-  for (guint i = 0; i < G_N_ELEMENTS(AtkInterfacesInitFunctions); i++) {
-    if (interface_mask & (1 << i)) {
-      g_type_add_interface_static(
-          type,
-          GetAtkInterfaceTypeFromWAIType(static_cast<WAIType>(i)),
-          &AtkInterfacesInitFunctions[i]);
-    }
-  }
-
-  return type;
-}
-
-BrowserAccessibilityAtk* browser_accessibility_new(
-    BrowserAccessibilityGtk* obj) {
-  GType type = GetAccessibilityTypeFromObject(obj);
-  AtkObject* atk_object = static_cast<AtkObject*>(g_object_new(type, 0));
-
-  atk_object_initialize(atk_object, obj);
-
-  return BROWSER_ACCESSIBILITY(atk_object);
-}
-
-void browser_accessibility_detach(BrowserAccessibilityAtk* atk_object) {
-}
-
-// static
-BrowserAccessibility* BrowserAccessibility::Create() {
-  return new BrowserAccessibilityGtk();
-}
-
-BrowserAccessibilityGtk::BrowserAccessibilityGtk() {
-  atk_object_ = ATK_OBJECT(browser_accessibility_new(this));
-}
-
-BrowserAccessibilityGtk::~BrowserAccessibilityGtk() {
-  browser_accessibility_detach(BROWSER_ACCESSIBILITY(atk_object_));
-}
-
-BrowserAccessibilityGtk* BrowserAccessibilityGtk::ToBrowserAccessibilityGtk() {
-  return this;
-}
-
-AtkObject* BrowserAccessibilityGtk::GetAtkObject() const {
-  if (!G_IS_OBJECT(atk_object_))
-    return NULL;
-  return atk_object_;
-}
-
-void BrowserAccessibilityGtk::PreInitialize() {
-  BrowserAccessibility::PreInitialize();
-  InitRoleAndState();
-
-  if (this->parent()) {
-    atk_object_set_parent(
-        atk_object_,
-        this->parent()->ToBrowserAccessibilityGtk()->GetAtkObject());
-  }
-}
-
-void BrowserAccessibilityGtk::InitRoleAndState() {
-  atk_acc_name_ = UTF16ToUTF8(name()).c_str();
-
-  switch(role_) {
-    case WebAccessibility::ROLE_BUTTON:
-      atk_role_ = ATK_ROLE_PUSH_BUTTON;
-      break;
-    case WebAccessibility::ROLE_CHECKBOX:
-      atk_role_ = ATK_ROLE_CHECK_BOX;
-      break;
-    case WebAccessibility::ROLE_COMBO_BOX:
-      atk_role_ = ATK_ROLE_COMBO_BOX;
-      break;
-    case WebAccessibility::ROLE_LINK:
-      atk_role_ = ATK_ROLE_LINK;
-      break;
-    case WebAccessibility::ROLE_RADIO_BUTTON:
-      atk_role_ = ATK_ROLE_RADIO_BUTTON;
-      break;
-    case WebAccessibility::ROLE_TEXTAREA:
-      atk_role_ = ATK_ROLE_ENTRY;
-      break;
-    case WebAccessibility::ROLE_TEXT_FIELD:
-      atk_role_ = ATK_ROLE_ENTRY;
-      break;
-    case WebAccessibility::ROLE_WEBCORE_LINK:
-      atk_role_ = ATK_ROLE_LINK;
-      break;
-    default:
-      atk_role_ = ATK_ROLE_UNKNOWN;
-      break;
-  }
-}
diff --git a/content/browser/accessibility/browser_accessibility_gtk.h b/content/browser/accessibility/browser_accessibility_gtk.h
deleted file mode 100644
index 222da8a..0000000
--- a/content/browser/accessibility/browser_accessibility_gtk.h
+++ /dev/null
@@ -1,93 +0,0 @@
-// 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.
-
-#ifndef CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_GTK_H_
-#define CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_GTK_H_
-#pragma once
-
-#include "base/compiler_specific.h"
-#include "content/browser/accessibility/browser_accessibility.h"
-#include "webkit/glue/webaccessibility.h"
-
-#include <atk/atk.h>
-
-using webkit_glue::WebAccessibility;
-
-class BrowserAccessibilityGtk;
-class BrowserAccessibilityManagerGtk;
-
-G_BEGIN_DECLS
-
-#define BROWSER_ACCESSIBILITY_TYPE (browser_accessibility_get_type())
-#define BROWSER_ACCESSIBILITY(obj) \
-    (G_TYPE_CHECK_INSTANCE_CAST( \
-             (obj), BROWSER_ACCESSIBILITY_TYPE, BrowserAccessibilityAtk))
-#define BROWSER_ACCESSIBILITY_CLASS(klass) \
-    (G_TYPE_CHECK_CLASS_CAST( \
-        (klass), BROWSER_ACCESSIBILITY_TYPE, BrowserAccessibilityAtkClass))
-#define IS_BROWSER_ACCESSIBILITY(obj) \
-    (G_TYPE_CHECK_INSTANCE_TYPE((obj), BROWSER_ACCESSIBILITY_TYPE))
-#define IS_BROWSER_ACCESSIBILITY_CLASS(klass) \
-    (G_TYPE_CHECK_CLASS_TYPE((klass), BROWSER_ACCESSIBILITY_TYPE))
-#define BROWSER_ACCESSIBILITY_GET_CLASS(obj) \
-    (G_TYPE_INSTANCE_GET_CLASS( \
-        (obj), BROWSER_ACCESSIBILITY_TYPE, BrowserAccessibilityAtkClass))
-
-typedef struct _BrowserAccessibilityAtk      BrowserAccessibilityAtk;
-typedef struct _BrowserAccessibilityAtkClass BrowserAccessibilityAtkClass;
-
-struct _BrowserAccessibilityAtk {
-  AtkObject parent;
-  BrowserAccessibilityGtk* m_object;
-};
-
-struct _BrowserAccessibilityAtkClass {
-  AtkObjectClass parent_class;
-};
-
-GType browser_accessibility_get_type (void) G_GNUC_CONST;
-
-BrowserAccessibilityAtk* browser_accessibility_new(
-    BrowserAccessibilityGtk* object);
-
-BrowserAccessibilityGtk* browser_accessibility_get_object(
-    BrowserAccessibilityAtk* atk_object);
-
-void browser_accessibility_detach (BrowserAccessibilityAtk* atk_object);
-
-AtkObject* browser_accessibility_get_focused_element(
-    BrowserAccessibilityAtk* atk_object);
-
-G_END_DECLS
-
-class BrowserAccessibilityGtk : public BrowserAccessibility {
- public:
-  BrowserAccessibilityGtk();
-
-  virtual ~BrowserAccessibilityGtk();
-
-  AtkObject* GetAtkObject() const;
-
-  AtkRole atk_role() { return atk_role_; }
-  const std::string& atk_acc_name() { return atk_acc_name_; }
-
-  // BrowserAccessibility methods.
-  virtual void PreInitialize() OVERRIDE;
-  virtual BrowserAccessibilityGtk* ToBrowserAccessibilityGtk() OVERRIDE;
-
- private:
-  virtual void InitRoleAndState();
-
-  // Give BrowserAccessibility::Create access to our constructor.
-  friend class BrowserAccessibility;
-
-  AtkObject* atk_object_;
-  AtkRole atk_role_;
-  std::string atk_acc_name_;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(BrowserAccessibilityGtk);
-};
-
-#endif  // CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_GTK_H_
diff --git a/content/browser/accessibility/browser_accessibility_mac.h b/content/browser/accessibility/browser_accessibility_mac.h
index 7eae766..c6fd27e 100644
--- a/content/browser/accessibility/browser_accessibility_mac.h
+++ b/content/browser/accessibility/browser_accessibility_mac.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// 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.
 
@@ -12,7 +12,6 @@
 
 #include "base/memory/scoped_nsobject.h"
 #include "content/browser/accessibility/browser_accessibility.h"
-#include "content/common/content_export.h"
 
 @class BrowserAccessibilityCocoa;
 
@@ -24,8 +23,6 @@ class BrowserAccessibilityMac : public BrowserAccessibility {
 
   // Overrides from BrowserAccessibility.
   virtual void DetachTree(std::vector<BrowserAccessibility*>* nodes) OVERRIDE;
-  CONTENT_EXPORT virtual BrowserAccessibilityMac*
-      ToBrowserAccessibilityMac() OVERRIDE;
 
   // The BrowserAccessibilityCocoa associated with us.
   BrowserAccessibilityCocoa* native_view() const {
diff --git a/content/browser/accessibility/browser_accessibility_mac.mm b/content/browser/accessibility/browser_accessibility_mac.mm
index ff0ab2f..6a209d8 100644
--- a/content/browser/accessibility/browser_accessibility_mac.mm
+++ b/content/browser/accessibility/browser_accessibility_mac.mm
@@ -53,6 +53,7 @@ void BrowserAccessibilityMac::DetachTree(
   BrowserAccessibility::DetachTree(nodes);
 }
 
-BrowserAccessibilityMac* BrowserAccessibilityMac::ToBrowserAccessibilityMac() {
-  return this;
+BrowserAccessibilityCocoa* BrowserAccessibility::toBrowserAccessibilityCocoa() {
+  return static_cast<BrowserAccessibilityMac*>(this)->
+      native_view();
 }
diff --git a/content/browser/accessibility/browser_accessibility_mac_unittest.mm b/content/browser/accessibility/browser_accessibility_mac_unittest.mm
index 1477c89..bb80935 100644
--- a/content/browser/accessibility/browser_accessibility_mac_unittest.mm
+++ b/content/browser/accessibility/browser_accessibility_mac_unittest.mm
@@ -8,7 +8,6 @@
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
 #include "content/browser/accessibility/browser_accessibility_cocoa.h"
-#include "content/browser/accessibility/browser_accessibility_mac.h"
 #include "content/browser/accessibility/browser_accessibility_manager.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #import "testing/gtest_mac.h"
@@ -78,8 +77,8 @@ class BrowserAccessibilityTest : public ui::CocoaTest {
     delegate_.reset([[MockAccessibilityDelegate alloc] init]);
     manager_.reset(
         BrowserAccessibilityManager::Create(delegate_, root, NULL));
-    accessibility_.reset([manager_->GetRoot()->ToBrowserAccessibilityMac()->
-        native_view() retain]);
+    accessibility_.reset([manager_->GetRoot()->toBrowserAccessibilityCocoa()
+        retain]);
   }
 
  protected:
diff --git a/content/browser/accessibility/browser_accessibility_manager.cc b/content/browser/accessibility/browser_accessibility_manager.cc
index 4440d28..9c5329d 100644
--- a/content/browser/accessibility/browser_accessibility_manager.cc
+++ b/content/browser/accessibility/browser_accessibility_manager.cc
@@ -21,11 +21,9 @@ BrowserAccessibility* BrowserAccessibilityFactory::Create() {
 // static
 int32 BrowserAccessibilityManager::next_child_id_ = -1;
 
-#if !defined(OS_MACOSX) && \
-    !(defined(OS_WIN) && !defined(USE_AURA)) && \
-    !defined(TOOLKIT_GTK)
-// We have subclassess of BrowserAccessibilityManager on Mac, Linux/GTK,
-// and non-Aura Win. For any other platform, instantiate the base class.
+#if (defined(OS_POSIX) && !defined(OS_MACOSX)) || defined(USE_AURA)
+// There's no OS-specific implementation of BrowserAccessibilityManager
+// on Unix, so just instantiate the base class.
 // static
 BrowserAccessibilityManager* BrowserAccessibilityManager::Create(
     gfx::NativeView parent_view,
diff --git a/content/browser/accessibility/browser_accessibility_manager.h b/content/browser/accessibility/browser_accessibility_manager.h
index 7e1757b..8b2d7fd 100644
--- a/content/browser/accessibility/browser_accessibility_manager.h
+++ b/content/browser/accessibility/browser_accessibility_manager.h
@@ -133,7 +133,7 @@ class CONTENT_EXPORT BrowserAccessibilityManager {
   gfx::NativeView GetParentView();
 
 #if defined(OS_WIN)
-  BrowserAccessibilityManagerWin* ToBrowserAccessibilityManagerWin();
+  BrowserAccessibilityManagerWin* toBrowserAccessibilityManagerWin();
 #endif
 
   // Return the object that has focus, if it's a descandant of the
diff --git a/content/browser/accessibility/browser_accessibility_manager_gtk.cc b/content/browser/accessibility/browser_accessibility_manager_gtk.cc
deleted file mode 100644
index 4bac86a..0000000
--- a/content/browser/accessibility/browser_accessibility_manager_gtk.cc
+++ /dev/null
@@ -1,71 +0,0 @@
-// 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_gtk.h"
-
-#include "content/browser/accessibility/browser_accessibility_gtk.h"
-#include "content/common/accessibility_messages.h"
-
-using webkit_glue::WebAccessibility;
-
-// static
-BrowserAccessibilityManager* BrowserAccessibilityManager::Create(
-    gfx::NativeView parent_view,
-    const WebAccessibility& src,
-    BrowserAccessibilityDelegate* delegate,
-    BrowserAccessibilityFactory* factory) {
-  return new BrowserAccessibilityManagerGtk(
-      parent_view,
-      src,
-      delegate,
-      factory);
-}
-
-BrowserAccessibilityManagerGtk::BrowserAccessibilityManagerGtk(
-    GtkWidget* parent_view,
-    const WebAccessibility& src,
-    BrowserAccessibilityDelegate* delegate,
-    BrowserAccessibilityFactory* factory)
-    : BrowserAccessibilityManager(parent_view, src, delegate, factory) {
-}
-
-BrowserAccessibilityManagerGtk::~BrowserAccessibilityManagerGtk() {
-}
-
-void BrowserAccessibilityManagerGtk::NotifyAccessibilityEvent(
-    int type,
-    BrowserAccessibility* node) {
-  if (!node->ToBrowserAccessibilityGtk())
-    return;
-  AtkObject* atk_object = node->ToBrowserAccessibilityGtk()->GetAtkObject();
-
-  switch (type) {
-    case AccessibilityNotificationChildrenChanged:
-      RecursivelySendChildrenChanged(GetRoot()->ToBrowserAccessibilityGtk());
-      break;
-    case AccessibilityNotificationFocusChanged:
-      // Note: atk_focus_tracker_notify may be deprecated in the future;
-      // follow this bug for the replacement:
-      // https://bugzilla.gnome.org/show_bug.cgi?id=649575#c4
-      g_signal_emit_by_name(atk_object, "focus-event", true);
-      atk_focus_tracker_notify(atk_object);
-      break;
-    default:
-      break;
-  }
-}
-
-void BrowserAccessibilityManagerGtk::RecursivelySendChildrenChanged(
-    BrowserAccessibilityGtk* node) {
-  AtkObject* atkObject = node->ToBrowserAccessibilityGtk()->GetAtkObject();
-  for (unsigned int i = 0; i < node->children().size(); ++i) {
-    BrowserAccessibilityGtk* child =
-        node->children()[i]->ToBrowserAccessibilityGtk();
-    g_signal_emit_by_name(atkObject,
-                          "children-changed::add",
-                          i,
-                          child->GetAtkObject());
-    RecursivelySendChildrenChanged(child);
-  }
-}
diff --git a/content/browser/accessibility/browser_accessibility_manager_gtk.h b/content/browser/accessibility/browser_accessibility_manager_gtk.h
deleted file mode 100644
index 4de6678..0000000
--- a/content/browser/accessibility/browser_accessibility_manager_gtk.h
+++ /dev/null
@@ -1,41 +0,0 @@
-// 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.
-
-#ifndef CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_MANAGER_GTK_H_
-#define CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_MANAGER_GTK_H_
-#pragma once
-
-#include "content/browser/accessibility/browser_accessibility_manager.h"
-#include "webkit/glue/webaccessibility.h"
-
-class BrowserAccessibilityGtk;
-struct ViewHostMsg_AccessibilityNotification_Params;
-
-using webkit_glue::WebAccessibility;
-
-// Manages a tree of BrowserAccessibilityGtk objects.
-class BrowserAccessibilityManagerGtk : public BrowserAccessibilityManager {
- public:
-  virtual ~BrowserAccessibilityManagerGtk();
-
-  // BrowserAccessibilityManager methods
-  virtual void NotifyAccessibilityEvent(int type, BrowserAccessibility* node)
-      OVERRIDE;
-
- private:
-  BrowserAccessibilityManagerGtk(
-      GtkWidget* parent_window,
-      const WebAccessibility& src,
-      BrowserAccessibilityDelegate* delegate,
-      BrowserAccessibilityFactory* factory);
-
-  void RecursivelySendChildrenChanged(BrowserAccessibilityGtk* node);
-
-  // Give BrowserAccessibilityManager::Create access to our constructor.
-  friend class BrowserAccessibilityManager;
-
-  DISALLOW_COPY_AND_ASSIGN(BrowserAccessibilityManagerGtk);
-};
-
-#endif  // CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_MANAGER_GTK_H_
diff --git a/content/browser/accessibility/browser_accessibility_manager_mac.mm b/content/browser/accessibility/browser_accessibility_manager_mac.mm
index e6163c6..92da9d5 100644
--- a/content/browser/accessibility/browser_accessibility_manager_mac.mm
+++ b/content/browser/accessibility/browser_accessibility_manager_mac.mm
@@ -6,7 +6,6 @@
 
 #import "base/logging.h"
 #import "content/browser/accessibility/browser_accessibility_cocoa.h"
-#import "content/browser/accessibility/browser_accessibility_mac.h"
 #include "content/common/accessibility_messages.h"
 
 // static
@@ -30,13 +29,6 @@ BrowserAccessibilityManagerMac::BrowserAccessibilityManagerMac(
 void BrowserAccessibilityManagerMac::NotifyAccessibilityEvent(
     int type,
     BrowserAccessibility* node) {
-  BrowserAccessibilityMac* mac_node = node->ToBrowserAccessibilityMac();
-  if (!mac_node)
-    return;
-  BrowserAccessibilityCocoa* native_node = mac_node->native_view();
-  if (!native_node)
-    return;
-
   // Refer to AXObjectCache.mm (webkit).
   NSString* event_id = @"";
   switch (type) {
@@ -106,5 +98,7 @@ void BrowserAccessibilityManagerMac::NotifyAccessibilityEvent(
       event_id = NSAccessibilityValueChangedNotification;
       break;
   }
+  BrowserAccessibilityCocoa* native_node = node->toBrowserAccessibilityCocoa();
+  DCHECK(native_node);
   NSAccessibilityPostNotification(native_node, event_id);
 }
diff --git a/content/browser/accessibility/browser_accessibility_manager_win.cc b/content/browser/accessibility/browser_accessibility_manager_win.cc
index b54d6fe..a00d233 100644
--- a/content/browser/accessibility/browser_accessibility_manager_win.cc
+++ b/content/browser/accessibility/browser_accessibility_manager_win.cc
@@ -23,7 +23,7 @@ BrowserAccessibilityManager* BrowserAccessibilityManager::Create(
 }
 
 BrowserAccessibilityManagerWin*
-BrowserAccessibilityManager::ToBrowserAccessibilityManagerWin() {
+BrowserAccessibilityManager::toBrowserAccessibilityManagerWin() {
   return static_cast<BrowserAccessibilityManagerWin*>(this);
 }
 
diff --git a/content/browser/accessibility/browser_accessibility_win.cc b/content/browser/accessibility/browser_accessibility_win.cc
index a0b1aa0..8d38e01 100644
--- a/content/browser/accessibility/browser_accessibility_win.cc
+++ b/content/browser/accessibility/browser_accessibility_win.cc
@@ -135,7 +135,7 @@ STDMETHODIMP BrowserAccessibilityRelation::get_target(
     return E_FAIL;
 
   *target = static_cast<IAccessible*>(
-      result->ToBrowserAccessibilityWin()->NewReference());
+      result->toBrowserAccessibilityWin()->NewReference());
   return S_OK;
 }
 
@@ -176,8 +176,8 @@ BrowserAccessibility* BrowserAccessibility::Create() {
   return instance->NewReference();
 }
 
-BrowserAccessibilityWin* BrowserAccessibilityWin::ToBrowserAccessibilityWin() {
-  return this;
+BrowserAccessibilityWin* BrowserAccessibility::toBrowserAccessibilityWin() {
+  return static_cast<BrowserAccessibilityWin*>(this);
 }
 
 BrowserAccessibilityWin::BrowserAccessibilityWin()
@@ -238,7 +238,7 @@ STDMETHODIMP BrowserAccessibilityWin::accHitTest(LONG x_left,
     child->lVal = CHILDID_SELF;
   } else {
     child->vt = VT_DISPATCH;
-    child->pdispVal = result->ToBrowserAccessibilityWin()->NewReference();
+    child->pdispVal = result->toBrowserAccessibilityWin()->NewReference();
   }
   return S_OK;
 }
@@ -307,7 +307,7 @@ STDMETHODIMP BrowserAccessibilityWin::accNavigate(
   }
 
   end->vt = VT_DISPATCH;
-  end->pdispVal = result->ToBrowserAccessibilityWin()->NewReference();
+  end->pdispVal = result->toBrowserAccessibilityWin()->NewReference();
   return S_OK;
 }
 
@@ -465,13 +465,11 @@ STDMETHODIMP BrowserAccessibilityWin::get_accParent(IDispatch** disp_parent) {
   if (!disp_parent)
     return E_INVALIDARG;
 
-  IAccessible* parent;
-  if (parent_) {
-    parent = parent_->ToBrowserAccessibilityWin();
-  } else {
+  IAccessible* parent = parent_->toBrowserAccessibilityWin();
+  if (parent == NULL) {
     // This happens if we're the root of the tree;
     // return the IAccessible for the window.
-    parent = manager_->ToBrowserAccessibilityManagerWin()->
+    parent = manager_->toBrowserAccessibilityManagerWin()->
              GetParentWindowIAccessible();
   }
 
@@ -568,7 +566,7 @@ STDMETHODIMP BrowserAccessibilityWin::get_accSelection(VARIANT* selected) {
       if (children_[i]->HasState(WebAccessibility::STATE_SELECTED)) {
         selected->vt = VT_DISPATCH;
         selected->pdispVal =
-            children_[i]->ToBrowserAccessibilityWin()->NewReference();
+            children_[i]->toBrowserAccessibilityWin()->NewReference();
         return S_OK;
       }
     }
@@ -583,7 +581,7 @@ STDMETHODIMP BrowserAccessibilityWin::get_accSelection(VARIANT* selected) {
     if (children_[i]->HasState(WebAccessibility::STATE_SELECTED)) {
       enum_variant->ItemAt(index)->vt = VT_DISPATCH;
       enum_variant->ItemAt(index)->pdispVal =
-        children_[i]->ToBrowserAccessibilityWin()->NewReference();
+        children_[i]->toBrowserAccessibilityWin()->NewReference();
       ++index;
     }
   }
@@ -1074,7 +1072,8 @@ STDMETHODIMP BrowserAccessibilityWin::get_columnIndex(
     return S_FALSE;
 
   int cell_id = unique_cell_ids_[cell_index];
-  BrowserAccessibility* cell = manager_->GetFromRendererID(cell_id);
+  BrowserAccessibilityWin* cell =
+      manager_->GetFromRendererID(cell_id)->toBrowserAccessibilityWin();
   int col_index;
   if (cell &&
       cell->GetIntAttribute(
@@ -1180,14 +1179,15 @@ STDMETHODIMP BrowserAccessibilityWin::get_rowDescription(
 
   for (int i = 0; i < columns; ++i) {
     int cell_id = cell_ids_[row * columns + i];
-    BrowserAccessibility* cell = manager_->GetFromRendererID(cell_id);
-    if (cell && cell->role() == WebAccessibility::ROLE_ROW_HEADER) {
-      if (cell->name().size() > 0) {
-        *description = SysAllocString(cell->name().c_str());
+    BrowserAccessibilityWin* cell =
+        manager_->GetFromRendererID(cell_id)->toBrowserAccessibilityWin();
+    if (cell && cell->role_ == WebAccessibility::ROLE_ROW_HEADER) {
+      if (cell->name_.size() > 0) {
+        *description = SysAllocString(cell->name_.c_str());
         return S_OK;
       }
 
-      return cell->ToBrowserAccessibilityWin()->GetStringAttributeAsBstr(
+      return cell->GetStringAttributeAsBstr(
           WebAccessibility::ATTR_DESCRIPTION, description);
     }
   }
@@ -1218,7 +1218,8 @@ STDMETHODIMP BrowserAccessibilityWin::get_rowExtentAt(
     return E_INVALIDARG;
 
   int cell_id = cell_ids_[row * columns + column];
-  BrowserAccessibility* cell = manager_->GetFromRendererID(cell_id);
+  BrowserAccessibilityWin* cell =
+      manager_->GetFromRendererID(cell_id)->toBrowserAccessibilityWin();
   int rowspan;
   if (cell &&
       cell->GetIntAttribute(
@@ -1254,7 +1255,8 @@ STDMETHODIMP BrowserAccessibilityWin::get_rowIndex(
     return S_FALSE;
 
   int cell_id = unique_cell_ids_[cell_index];
-  BrowserAccessibility* cell = manager_->GetFromRendererID(cell_id);
+  BrowserAccessibilityWin* cell =
+      manager_->GetFromRendererID(cell_id)->toBrowserAccessibilityWin();
   int cell_row_index;
   if (cell &&
       cell->GetIntAttribute(
@@ -1386,7 +1388,8 @@ STDMETHODIMP BrowserAccessibilityWin::get_rowColumnExtentsAtIndex(
     return S_FALSE;
 
   int cell_id = unique_cell_ids_[index];
-  BrowserAccessibility* cell = manager_->GetFromRendererID(cell_id);
+  BrowserAccessibilityWin* cell =
+      manager_->GetFromRendererID(cell_id)->toBrowserAccessibilityWin();
   int rowspan;
   int colspan;
   if (cell &&
@@ -1523,8 +1526,9 @@ STDMETHODIMP BrowserAccessibilityWin::get_columnHeaderCells(
 
   for (int i = 0; i < rows; ++i) {
     int cell_id = table->cell_ids()[i * columns + column];
-    BrowserAccessibility* cell = manager_->GetFromRendererID(cell_id);
-    if (cell && cell->role() == WebAccessibility::ROLE_COLUMN_HEADER)
+    BrowserAccessibilityWin* cell =
+        manager_->GetFromRendererID(cell_id)->toBrowserAccessibilityWin();
+    if (cell && cell->role_ == WebAccessibility::ROLE_COLUMN_HEADER)
       (*n_column_header_cells)++;
   }
 
@@ -1533,11 +1537,11 @@ STDMETHODIMP BrowserAccessibilityWin::get_columnHeaderCells(
   int index = 0;
   for (int i = 0; i < rows; ++i) {
     int cell_id = table->cell_ids()[i * columns + column];
-    BrowserAccessibility* cell = manager_->GetFromRendererID(cell_id);
-    if (cell && cell->role() == WebAccessibility::ROLE_COLUMN_HEADER) {
+    BrowserAccessibilityWin* cell =
+        manager_->GetFromRendererID(cell_id)->toBrowserAccessibilityWin();
+    if (cell && cell->role_ == WebAccessibility::ROLE_COLUMN_HEADER) {
       (*cell_accessibles)[index] =
-          static_cast<IAccessible*>(
-              cell->ToBrowserAccessibilityWin()->NewReference());
+          static_cast<IAccessible*>(cell->NewReference());
       ++index;
     }
   }
@@ -1620,8 +1624,9 @@ STDMETHODIMP BrowserAccessibilityWin::get_rowHeaderCells(
 
   for (int i = 0; i < columns; ++i) {
     int cell_id = table->cell_ids()[row * columns + i];
-    BrowserAccessibility* cell = manager_->GetFromRendererID(cell_id);
-    if (cell && cell->role() == WebAccessibility::ROLE_ROW_HEADER)
+    BrowserAccessibilityWin* cell =
+        manager_->GetFromRendererID(cell_id)->toBrowserAccessibilityWin();
+    if (cell && cell->role_ == WebAccessibility::ROLE_ROW_HEADER)
       (*n_row_header_cells)++;
   }
 
@@ -1630,11 +1635,11 @@ STDMETHODIMP BrowserAccessibilityWin::get_rowHeaderCells(
   int index = 0;
   for (int i = 0; i < columns; ++i) {
     int cell_id = table->cell_ids()[row * columns + i];
-    BrowserAccessibility* cell = manager_->GetFromRendererID(cell_id);
-    if (cell && cell->role() == WebAccessibility::ROLE_ROW_HEADER) {
+    BrowserAccessibilityWin* cell =
+        manager_->GetFromRendererID(cell_id)->toBrowserAccessibilityWin();
+    if (cell && cell->role_ == WebAccessibility::ROLE_ROW_HEADER) {
       (*cell_accessibles)[index] =
-          static_cast<IAccessible*>(
-              cell->ToBrowserAccessibilityWin()->NewReference());
+          static_cast<IAccessible*>(cell->NewReference());
       ++index;
     }
   }
@@ -1732,7 +1737,7 @@ STDMETHODIMP BrowserAccessibilityWin::get_table(
   }
 
   *table = static_cast<IAccessibleTable*>(
-      find_table->ToBrowserAccessibilityWin()->NewReference());
+      find_table->toBrowserAccessibilityWin()->NewReference());
 
   return S_OK;
 }
@@ -2090,7 +2095,7 @@ STDMETHODIMP BrowserAccessibilityWin::get_hyperlink(
   }
 
   BrowserAccessibilityWin* child =
-      children_[hyperlinks_[index]]->ToBrowserAccessibilityWin();
+      children_[hyperlinks_[index]]->toBrowserAccessibilityWin();
   *hyperlink = static_cast<IAccessibleHyperlink*>(child->NewReference());
   return S_OK;
 }
@@ -2392,12 +2397,7 @@ STDMETHODIMP BrowserAccessibilityWin::get_parentNode(ISimpleDOMNode** node) {
   if (!node)
     return E_INVALIDARG;
 
-  if (!parent_) {
-    *node = NULL;
-    return S_FALSE;
-  }
-
-  *node = parent_->ToBrowserAccessibilityWin()->NewReference();
+  *node = parent_->toBrowserAccessibilityWin()->NewReference();
   return S_OK;
 }
 
@@ -2409,7 +2409,7 @@ STDMETHODIMP BrowserAccessibilityWin::get_firstChild(ISimpleDOMNode** node)  {
     return E_INVALIDARG;
 
   if (children_.size()) {
-    *node = children_[0]->ToBrowserAccessibilityWin()->NewReference();
+    *node = children_[0]->toBrowserAccessibilityWin()->NewReference();
     return S_OK;
   } else {
     *node = NULL;
@@ -2425,7 +2425,7 @@ STDMETHODIMP BrowserAccessibilityWin::get_lastChild(ISimpleDOMNode** node) {
     return E_INVALIDARG;
 
   if (children_.size()) {
-    *node = children_[children_.size() - 1]->ToBrowserAccessibilityWin()->
+    *node = children_[children_.size() - 1]->toBrowserAccessibilityWin()->
         NewReference();
     return S_OK;
   } else {
@@ -2444,7 +2444,7 @@ STDMETHODIMP BrowserAccessibilityWin::get_previousSibling(
 
   if (parent_ && index_in_parent_ > 0) {
     *node = parent_->children()[index_in_parent_ - 1]->
-        ToBrowserAccessibilityWin()->NewReference();
+        toBrowserAccessibilityWin()->NewReference();
     return S_OK;
   } else {
     *node = NULL;
@@ -2463,7 +2463,7 @@ STDMETHODIMP BrowserAccessibilityWin::get_nextSibling(ISimpleDOMNode** node) {
       index_in_parent_ >= 0 &&
       index_in_parent_ < static_cast<int>(parent_->children().size()) - 1) {
     *node = parent_->children()[index_in_parent_ + 1]->
-        ToBrowserAccessibilityWin()->NewReference();
+        toBrowserAccessibilityWin()->NewReference();
     return S_OK;
   } else {
     *node = NULL;
@@ -2481,7 +2481,7 @@ STDMETHODIMP BrowserAccessibilityWin::get_childAt(
     return E_INVALIDARG;
 
   if (child_index < children_.size()) {
-    *node = children_[child_index]->ToBrowserAccessibilityWin()->NewReference();
+    *node = children_[child_index]->toBrowserAccessibilityWin()->NewReference();
     return S_OK;
   } else {
     *node = NULL;
@@ -2848,9 +2848,9 @@ BrowserAccessibilityWin* BrowserAccessibilityWin::GetTargetFromChildID(
     return this;
 
   if (child_id >= 1 && child_id <= static_cast<LONG>(children_.size()))
-    return children_[child_id - 1]->ToBrowserAccessibilityWin();
+    return children_[child_id - 1]->toBrowserAccessibilityWin();
 
-  return manager_->GetFromChildID(child_id)->ToBrowserAccessibilityWin();
+  return manager_->GetFromChildID(child_id)->toBrowserAccessibilityWin();
 }
 
 HRESULT BrowserAccessibilityWin::GetStringAttributeAsBstr(
@@ -2944,8 +2944,7 @@ LONG BrowserAccessibilityWin::FindBoundary(
 
 BrowserAccessibilityWin* BrowserAccessibilityWin::GetFromRendererID(
     int32 renderer_id) {
-  BrowserAccessibility* result = manager_->GetFromRendererID(renderer_id);
-  return result ? result->ToBrowserAccessibilityWin() : NULL;
+  return manager_->GetFromRendererID(renderer_id)->toBrowserAccessibilityWin();
 }
 
 void BrowserAccessibilityWin::InitRoleAndState() {
diff --git a/content/browser/accessibility/browser_accessibility_win.h b/content/browser/accessibility/browser_accessibility_win.h
index 60ca7db..6386e5f 100644
--- a/content/browser/accessibility/browser_accessibility_win.h
+++ b/content/browser/accessibility/browser_accessibility_win.h
@@ -13,7 +13,6 @@
 
 #include <vector>
 
-#include "base/compiler_specific.h"
 #include "content/browser/accessibility/browser_accessibility.h"
 #include "content/common/content_export.h"
 #include "third_party/iaccessible2/ia2_api_all.h"
@@ -101,8 +100,6 @@ BrowserAccessibilityWin
   CONTENT_EXPORT virtual void PostInitialize();
   CONTENT_EXPORT virtual void NativeAddReference();
   CONTENT_EXPORT virtual void NativeReleaseReference();
-  CONTENT_EXPORT virtual BrowserAccessibilityWin* ToBrowserAccessibilityWin()
-      OVERRIDE;
 
   //
   // IAccessible methods.
diff --git a/content/browser/accessibility/browser_accessibility_win_unittest.cc b/content/browser/accessibility/browser_accessibility_win_unittest.cc
index 7841d4b..4afcd27 100644
--- a/content/browser/accessibility/browser_accessibility_win_unittest.cc
+++ b/content/browser/accessibility/browser_accessibility_win_unittest.cc
@@ -115,7 +115,7 @@ TEST_F(BrowserAccessibilityTest, TestNoLeaks) {
           new CountedBrowserAccessibilityFactory());
   ASSERT_EQ(3, CountedBrowserAccessibility::global_obj_count_);
   IAccessible* root_accessible =
-      manager->GetRoot()->ToBrowserAccessibilityWin();
+      manager->GetRoot()->toBrowserAccessibilityWin();
   IDispatch* root_iaccessible = NULL;
   IDispatch* child1_iaccessible = NULL;
   VARIANT var_child;
@@ -170,7 +170,7 @@ TEST_F(BrowserAccessibilityTest, TestChildrenChange) {
   // Query for the text IAccessible and verify that it returns "old text" as its
   // value.
   base::win::ScopedComPtr<IDispatch> text_dispatch;
-  HRESULT hr = manager->GetRoot()->ToBrowserAccessibilityWin()->get_accChild(
+  HRESULT hr = manager->GetRoot()->toBrowserAccessibilityWin()->get_accChild(
       CreateI4Variant(1), text_dispatch.Receive());
   ASSERT_EQ(S_OK, hr);
 
@@ -199,7 +199,7 @@ TEST_F(BrowserAccessibilityTest, TestChildrenChange) {
 
   // Query for the text IAccessible and verify that it now returns "new text"
   // as its value.
-  hr = manager->GetRoot()->ToBrowserAccessibilityWin()->get_accChild(
+  hr = manager->GetRoot()->toBrowserAccessibilityWin()->get_accChild(
       CreateI4Variant(1),
       text_dispatch.Receive());
   ASSERT_EQ(S_OK, hr);
@@ -297,9 +297,9 @@ TEST_F(BrowserAccessibilityTest, TestTextBoundaries) {
   ASSERT_EQ(2, CountedBrowserAccessibility::global_obj_count_);
 
   BrowserAccessibilityWin* root_obj =
-      manager->GetRoot()->ToBrowserAccessibilityWin();
+      manager->GetRoot()->toBrowserAccessibilityWin();
   BrowserAccessibilityWin* text1_obj =
-      root_obj->GetChild(0)->ToBrowserAccessibilityWin();
+      root_obj->GetChild(0)->toBrowserAccessibilityWin();
 
   BSTR text;
   long start;
@@ -393,7 +393,7 @@ TEST_F(BrowserAccessibilityTest, TestSimpleHypertext) {
   ASSERT_EQ(3, CountedBrowserAccessibility::global_obj_count_);
 
   BrowserAccessibilityWin* root_obj =
-      manager->GetRoot()->ToBrowserAccessibilityWin();
+      manager->GetRoot()->toBrowserAccessibilityWin();
 
   BSTR text;
 
@@ -477,7 +477,7 @@ TEST_F(BrowserAccessibilityTest, TestComplexHypertext) {
   ASSERT_EQ(7, CountedBrowserAccessibility::global_obj_count_);
 
   BrowserAccessibilityWin* root_obj =
-      manager->GetRoot()->ToBrowserAccessibilityWin();
+      manager->GetRoot()->toBrowserAccessibilityWin();
 
   BSTR text;
 
diff --git a/content/browser/accessibility/dump_accessibility_tree_helper_mac.mm b/content/browser/accessibility/dump_accessibility_tree_helper_mac.mm
index afdd1f1..50c40cd 100644
--- a/content/browser/accessibility/dump_accessibility_tree_helper_mac.mm
+++ b/content/browser/accessibility/dump_accessibility_tree_helper_mac.mm
@@ -15,8 +15,7 @@ void DumpAccessibilityTreeHelper::Initialize() {}
 
 string16 DumpAccessibilityTreeHelper::ToString(BrowserAccessibility* node,
                                                char* prefix) {
-  BrowserAccessibilityCocoa* cocoa_node = node->ToBrowserAccessibilityMac()->
-      native_view();
+  BrowserAccessibilityCocoa* cocoa_node = node->toBrowserAccessibilityCocoa();
   NSString* dump =
       [NSString stringWithFormat:@"%s%@ "
                                   "subrole=%@ "
diff --git a/content/browser/accessibility/dump_accessibility_tree_helper_win.cc b/content/browser/accessibility/dump_accessibility_tree_helper_win.cc
index f1d2c80..a567b2b 100644
--- a/content/browser/accessibility/dump_accessibility_tree_helper_win.cc
+++ b/content/browser/accessibility/dump_accessibility_tree_helper_win.cc
@@ -197,7 +197,7 @@ string16 DumpAccessibilityTreeHelper::ToString(
   if (role_string_map.empty())
     Initialize();
 
-  BrowserAccessibilityWin* acc_obj = node->ToBrowserAccessibilityWin();
+  BrowserAccessibilityWin* acc_obj = node->toBrowserAccessibilityWin();
   string16 state;
   std::map<int32, string16>::iterator it;
 
diff --git a/content/browser/renderer_host/render_widget_host_view_gtk.cc b/content/browser/renderer_host/render_widget_host_view_gtk.cc
index 91c3ddf..15a0073 100644
--- a/content/browser/renderer_host/render_widget_host_view_gtk.cc
+++ b/content/browser/renderer_host/render_widget_host_view_gtk.cc
@@ -27,7 +27,6 @@
 #include "base/time.h"
 #include "base/utf_offset_string_conversions.h"
 #include "base/utf_string_conversions.h"
-#include "content/browser/accessibility/browser_accessibility_gtk.h"
 #include "content/browser/renderer_host/backing_store_gtk.h"
 #include "content/browser/renderer_host/gtk_im_context_wrapper.h"
 #include "content/browser/renderer_host/gtk_key_bindings_handler.h"
@@ -112,11 +111,6 @@ using WebKit::WebMouseWheelEvent;
 // static methods.
 class RenderWidgetHostViewGtkWidget {
  public:
-  static AtkObject* GetAccessible(void* userdata) {
-    return (static_cast<RenderWidgetHostViewGtk*>(userdata))->
-        GetAccessible();
-  }
-
   static GtkWidget* CreateNewWidget(RenderWidgetHostViewGtk* host_view) {
     GtkWidget* widget = gtk_preserve_window_new();
     gtk_widget_set_name(widget, "chrome-render-widget-host-view");
@@ -175,10 +169,6 @@ class RenderWidgetHostViewGtkWidget {
     g_signal_connect_after(widget, "scroll-event",
                            G_CALLBACK(OnMouseScrollEvent), host_view);
 
-    // Route calls to get_accessible to the view.
-    gtk_preserve_window_set_accessible_factory(
-        GTK_PRESERVE_WINDOW(widget), GetAccessible, host_view);
-
     return widget;
   }
 
@@ -1414,69 +1404,3 @@ void content::RenderWidgetHostViewPort::GetDefaultScreenInfo(
       gdk_display_get_default_group(gdk_display_get_default());
   content::GetScreenInfoFromNativeWindow(gdk_window, results);
 }
-
-void RenderWidgetHostViewGtk::SetAccessibilityFocus(int acc_obj_id) {
-  if (!host_)
-    return;
-
-  host_->AccessibilitySetFocus(acc_obj_id);
-}
-
-void RenderWidgetHostViewGtk::AccessibilityDoDefaultAction(int acc_obj_id) {
-  if (!host_)
-    return;
-
-  host_->AccessibilityDoDefaultAction(acc_obj_id);
-}
-
-void RenderWidgetHostViewGtk::AccessibilityScrollToMakeVisible(
-    int acc_obj_id, gfx::Rect subfocus) {
-  if (!host_)
-    return;
-
-  host_->AccessibilityScrollToMakeVisible(acc_obj_id, subfocus);
-}
-
-void RenderWidgetHostViewGtk::AccessibilityScrollToPoint(
-    int acc_obj_id, gfx::Point point) {
-  if (!host_)
-    return;
-
-  host_->AccessibilityScrollToPoint(acc_obj_id, point);
-}
-
-void RenderWidgetHostViewGtk::AccessibilitySetTextSelection(
-    int acc_obj_id, int start_offset, int end_offset) {
-  if (!host_)
-    return;
-
-  host_->AccessibilitySetTextSelection(acc_obj_id, start_offset, end_offset);
-}
-
-void RenderWidgetHostViewGtk::OnAccessibilityNotifications(
-    const std::vector<AccessibilityHostMsg_NotificationParams>& params) {
-  if (!browser_accessibility_manager_.get()) {
-    GtkWidget* parent = gtk_widget_get_parent(view_.get());
-    browser_accessibility_manager_.reset(
-        BrowserAccessibilityManager::CreateEmptyDocument(
-            parent, static_cast<WebAccessibility::State>(0), this));
-  }
-  browser_accessibility_manager_->OnAccessibilityNotifications(params);
-}
-
-AtkObject* RenderWidgetHostViewGtk::GetAccessible() {
-  RenderWidgetHostImpl::From(GetRenderWidgetHost())->
-      SetAccessibilityMode(AccessibilityModeComplete);
-
-  if (!browser_accessibility_manager_.get()) {
-    GtkWidget* parent = gtk_widget_get_parent(view_.get());
-    browser_accessibility_manager_.reset(
-        BrowserAccessibilityManager::CreateEmptyDocument(
-            parent, static_cast<WebAccessibility::State>(0), this));
-  }
-  BrowserAccessibilityGtk* root =
-      browser_accessibility_manager_->GetRoot()->ToBrowserAccessibilityGtk();
-
-  atk_object_set_role(root->GetAtkObject(), ATK_ROLE_HTML_CONTAINER);
-  return root->GetAtkObject();
-}
diff --git a/content/browser/renderer_host/render_widget_host_view_gtk.h b/content/browser/renderer_host/render_widget_host_view_gtk.h
index db9a6a7..0f7c00a 100644
--- a/content/browser/renderer_host/render_widget_host_view_gtk.h
+++ b/content/browser/renderer_host/render_widget_host_view_gtk.h
@@ -13,7 +13,6 @@
 
 #include "base/memory/scoped_ptr.h"
 #include "base/time.h"
-#include "content/browser/accessibility/browser_accessibility_manager.h"
 #include "content/browser/renderer_host/render_widget_host_view_base.h"
 #include "content/common/content_export.h"
 #include "ui/base/animation/animation_delegate.h"
@@ -43,9 +42,7 @@ typedef struct _GtkSelectionData GtkSelectionData;
 // -----------------------------------------------------------------------------
 // See comments in render_widget_host_view.h about this class and its members.
 // -----------------------------------------------------------------------------
-class CONTENT_EXPORT RenderWidgetHostViewGtk
-    : public content::RenderWidgetHostViewBase,
-      public BrowserAccessibilityDelegate {
+class RenderWidgetHostViewGtk : public content::RenderWidgetHostViewBase {
  public:
   virtual ~RenderWidgetHostViewGtk();
 
@@ -125,9 +122,6 @@ class CONTENT_EXPORT RenderWidgetHostViewGtk
   virtual gfx::GLSurfaceHandle GetCompositingSurface() OVERRIDE;
   virtual bool LockMouse() OVERRIDE;
   virtual void UnlockMouse() OVERRIDE;
-  virtual void OnAccessibilityNotifications(
-      const std::vector<AccessibilityHostMsg_NotificationParams>& params)
-      OVERRIDE;
 
   // If the widget is aligned with an edge of the monitor its on and the user
   // attempts to drag past that edge we track the number of times it has
@@ -152,19 +146,6 @@ class CONTENT_EXPORT RenderWidgetHostViewGtk
 
   bool RetrieveSurrounding(std::string* text, size_t* cursor_index);
 
-  // BrowserAccessibilityDelegate implementation.
-  virtual void SetAccessibilityFocus(int acc_obj_id) OVERRIDE;
-  virtual void AccessibilityDoDefaultAction(int acc_obj_id) OVERRIDE;
-  virtual void AccessibilityScrollToMakeVisible(
-      int acc_obj_id, gfx::Rect subfocus) OVERRIDE;
-  virtual void AccessibilityScrollToPoint(
-      int acc_obj_id, gfx::Point point) OVERRIDE;
-  virtual void AccessibilitySetTextSelection(
-      int acc_obj_id, int start_offset, int end_offset) OVERRIDE;
-
-  // Get the root of the AtkObject* tree for accessibility.
-  AtkObject* GetAccessible();
-
  protected:
   friend class content::RenderWidgetHostView;
 
@@ -306,10 +287,6 @@ class CONTENT_EXPORT RenderWidgetHostViewGtk
   // menus and drags.
   GdkEventButton* last_mouse_down_;
 
-  // Instance of accessibility information for the root of the AtkObject
-  // tree representation of the WebKit render tree.
-  scoped_ptr<BrowserAccessibilityManager> browser_accessibility_manager_;
-
   ui::GtkSignalRegistrar signals_;
 };
 
diff --git a/content/browser/renderer_host/render_widget_host_view_mac.mm b/content/browser/renderer_host/render_widget_host_view_mac.mm
index c3acf4b..83f76a8 100644
--- a/content/browser/renderer_host/render_widget_host_view_mac.mm
+++ b/content/browser/renderer_host/render_widget_host_view_mac.mm
@@ -20,7 +20,6 @@
 #include "base/sys_string_conversions.h"
 #include "base/utf_string_conversions.h"
 #import "content/browser/accessibility/browser_accessibility_cocoa.h"
-#import "content/browser/accessibility/browser_accessibility_mac.h"
 #include "content/browser/accessibility/browser_accessibility_manager.h"
 #include "content/browser/plugin_process_host.h"
 #import "content/browser/renderer_host/accelerated_plugin_view_mac.h"
@@ -2107,7 +2106,7 @@ void RenderWidgetHostViewMac::SetTextInputActive(bool active) {
           [attribute isEqualToString:NSAccessibilityContentsAttribute]) &&
       manager) {
     return [NSArray arrayWithObjects:manager->
-        GetRoot()->ToBrowserAccessibilityMac()->native_view(), nil];
+        GetRoot()->toBrowserAccessibilityCocoa(), nil];
   } else if ([attribute isEqualToString:NSAccessibilityRoleAttribute]) {
     return NSAccessibilityScrollAreaRole;
   }
@@ -2130,7 +2129,7 @@ void RenderWidgetHostViewMac::SetTextInputActive(bool active) {
   localPoint.y = NSHeight([self bounds]) - localPoint.y;
   BrowserAccessibilityCocoa* root = renderWidgetHostView_->
       GetBrowserAccessibilityManager()->
-          GetRoot()->ToBrowserAccessibilityMac()->native_view();
+          GetRoot()->toBrowserAccessibilityCocoa();
   id obj = [root accessibilityHitTest:localPoint];
   return obj;
 }
@@ -2144,7 +2143,7 @@ void RenderWidgetHostViewMac::SetTextInputActive(bool active) {
       renderWidgetHostView_->GetBrowserAccessibilityManager();
   // Only child is root.
   if (manager &&
-      manager->GetRoot()->ToBrowserAccessibilityMac()->native_view() == child) {
+      manager->GetRoot()->toBrowserAccessibilityCocoa() == child) {
     return 0;
   } else {
     return NSNotFound;
@@ -2159,7 +2158,7 @@ void RenderWidgetHostViewMac::SetTextInputActive(bool active) {
     DCHECK(focused_item);
     if (focused_item) {
       BrowserAccessibilityCocoa* focused_item_cocoa =
-          focused_item->ToBrowserAccessibilityMac()->native_view();
+          focused_item->toBrowserAccessibilityCocoa();
       DCHECK(focused_item_cocoa);
       if (focused_item_cocoa)
         return focused_item_cocoa;
diff --git a/content/browser/renderer_host/render_widget_host_view_win.cc b/content/browser/renderer_host/render_widget_host_view_win.cc
index 60b596c..5cd8d27 100644
--- a/content/browser/renderer_host/render_widget_host_view_win.cc
+++ b/content/browser/renderer_host/render_widget_host_view_win.cc
@@ -478,7 +478,7 @@ RenderWidgetHostViewWin::GetNativeViewAccessible() {
   }
 
   return GetBrowserAccessibilityManager()->GetRoot()->
-      ToBrowserAccessibilityWin();
+      toBrowserAccessibilityWin();
 }
 
 void RenderWidgetHostViewWin::MovePluginWindows(
diff --git a/content/content_browser.gypi b/content/content_browser.gypi
index 10efd83..36ab74e 100644
--- a/content/content_browser.gypi
+++ b/content/content_browser.gypi
@@ -166,14 +166,10 @@
     'browser/accessibility/browser_accessibility_cocoa.h',
     'browser/accessibility/browser_accessibility_cocoa.mm',
     'browser/accessibility/browser_accessibility_delegate_mac.h',
-    'browser/accessibility/browser_accessibility_gtk.cc',
-    'browser/accessibility/browser_accessibility_gtk.h',
     'browser/accessibility/browser_accessibility_mac.h',
     'browser/accessibility/browser_accessibility_mac.mm',
     'browser/accessibility/browser_accessibility_manager.cc',
     'browser/accessibility/browser_accessibility_manager.h',
-    'browser/accessibility/browser_accessibility_manager_gtk.cc',
-    'browser/accessibility/browser_accessibility_manager_gtk.h',
     'browser/accessibility/browser_accessibility_manager_mac.h',
     'browser/accessibility/browser_accessibility_manager_mac.mm',
     'browser/accessibility/browser_accessibility_manager_win.cc',