Add initial GTK web accessibility framework (third attempt).

content/browser/accessibility/browser_accessibility_manager.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/accessibility/browser_accessibility_manager.h"
 
 #include "base/logging.h"
 #include "content/browser/accessibility/browser_accessibility.h"
 #include "content/common/accessibility_messages.h"
 
 using webkit_glue::WebAccessibility;
 
 BrowserAccessibility* BrowserAccessibilityFactory::Create() {
   return BrowserAccessibility::Create();
 }
 
 // Start child IDs at -1 and decrement each time, because clients use
 // child IDs of 1, 2, 3, ... to access the children of an object by
 // index, so we use negative IDs to clearly distinguish between indices
 // and unique IDs.
 // static
 int32 BrowserAccessibilityManager::next_child_id_ = -1;
 
-#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.
+#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.
 // static
 BrowserAccessibilityManager* BrowserAccessibilityManager::Create(
     gfx::NativeView parent_view,
     const WebAccessibility& src,
     BrowserAccessibilityDelegate* delegate,
     BrowserAccessibilityFactory* factory) {
   return new BrowserAccessibilityManager(
       parent_view, src, delegate, factory);
 }
 #endif
@@ skipping 328 matching lines @@
   // is so that we send a single ObjectShow event for the root of a subtree
   // that just appeared for the first time, but not on any descendant of
   // that subtree.
   if (send_show_events)
     NotifyAccessibilityEvent(AccessibilityNotificationObjectShow, instance);
 
   instance->PostInitialize();
 
   return instance;
 }