Views a11y: Implement AXPlatformNode::FromNativeViewAccessible on all platforms.

ui/accessibility/platform/ax_platform_node.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/accessibility/platform/ax_platform_node.h"
 
 #include "base/containers/hash_tables.h"
 #include "base/lazy_instance.h"
 #include "build/build_config.h"
 #include "ui/accessibility/ax_node_data.h"
 #include "ui/accessibility/platform/ax_platform_node_delegate.h"
 #include "ui/accessibility/platform/ax_platform_unique_id.h"
 
 namespace ui {
 
 namespace {
 
 using UniqueIdMap = base::hash_map<int32_t, AXPlatformNode*>;
 // Map from each AXPlatformNode's unique id to its instance.
 base::LazyInstance<UniqueIdMap>::DestructorAtExit g_unique_id_map =
     LAZY_INSTANCE_INITIALIZER;
 }
 
-#if !defined(OS_WIN)
-// This is the default implementation for platforms where native views
-// accessibility is unsupported or unfinished.
-//
-// static
-AXPlatformNode* AXPlatformNode::FromNativeViewAccessible(
-    gfx::NativeViewAccessible accessible) {
-  return nullptr;
-}
-#endif
-
 AXPlatformNode::AXPlatformNode() : unique_id_(GetNextAXPlatformNodeUniqueId()) {
   g_unique_id_map.Get()[unique_id_] = this;
 }
 
 AXPlatformNode::~AXPlatformNode() {
   if (unique_id_)
     g_unique_id_map.Get().erase(unique_id_);
 }
 
 void AXPlatformNode::Destroy() {
   g_unique_id_map.Get().erase(unique_id_);
   unique_id_ = 0;
 }
 
 AXPlatformNode* AXPlatformNode::GetFromUniqueId(int32_t unique_id) {
   UniqueIdMap* unique_ids = g_unique_id_map.Pointer();
   auto iter = unique_ids->find(unique_id);
   if (iter != unique_ids->end())
     return iter->second;
 
   return nullptr;
 }
 
 }  // namespace ui