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

ui/accessibility/platform/ax_platform_node_mac.mm

 // 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.
 
 #import "ui/accessibility/platform/ax_platform_node_mac.h"
 
 #import <Cocoa/Cocoa.h>
 #include <stddef.h>
 
 #include "base/macros.h"
 #include "base/strings/sys_string_conversions.h"
 #include "ui/accessibility/ax_action_data.h"
 #include "ui/accessibility/ax_node_data.h"
 #include "ui/accessibility/ax_role_properties.h"
+#include "ui/accessibility/platform/ax_platform_node.h"
 #include "ui/accessibility/platform/ax_platform_node_delegate.h"
 #include "ui/base/l10n/l10n_util.h"
 #import "ui/gfx/mac/coordinate_conversion.h"
 #include "ui/strings/grit/ui_strings.h"
 
 namespace {
 
 struct RoleMapEntry {
   ui::AXRole value;
   NSString* nativeValue;
@@ skipping 198 matching lines @@
       target, [AXPlatformNodeCocoa nativeNotificationFromAXEvent:event_type]);
 }
 
 }  // namespace
 
 @interface AXPlatformNodeCocoa ()
 // Helper function for string attributes that don't require extra processing.
 - (NSString*)getStringAttribute:(ui::AXStringAttribute)attribute;
 @end
 
-@implementation AXPlatformNodeCocoa
+@implementation AXPlatformNodeCocoa {
+  ui::AXPlatformNodeBase* node_;  // Weak. Retains us.
+}
+
+@synthesize node = node_;
 
 // A mapping of AX roles to native roles.
 + (NSString*)nativeRoleFromAXRole:(ui::AXRole)role {
   CR_DEFINE_STATIC_LOCAL(RoleMap, role_map, (BuildRoleMap()));
   RoleMap::iterator it = role_map.find(role);
   return it != role_map.end() ? it->second : NSAccessibilityUnknownRole;
 }
 
 // A mapping of AX roles to native subroles.
 + (NSString*)nativeSubroleFromAXRole:(ui::AXRole)role {
@@ skipping 399 matching lines @@
 
 namespace ui {
 
 // static
 AXPlatformNode* AXPlatformNode::Create(AXPlatformNodeDelegate* delegate) {
   AXPlatformNodeBase* node = new AXPlatformNodeMac();
   node->Init(delegate);
   return node;
 }
 
+// static
+AXPlatformNode* AXPlatformNode::FromNativeViewAccessible(
+    gfx::NativeViewAccessible accessible) {
+  if ([accessible isKindOfClass:[AXPlatformNodeCocoa class]])
+    return [accessible node];
+  return nullptr;
+}
+
 AXPlatformNodeMac::AXPlatformNodeMac() {
 }
 
 AXPlatformNodeMac::~AXPlatformNodeMac() {
 }
 
 void AXPlatformNodeMac::Destroy() {
   if (native_node_)
     [native_node_ detach];
   AXPlatformNodeBase::Destroy();
@@ skipping 22 matching lines @@
   }
   NotifyMacEvent(native_node_, event_type);
 }
 
 int AXPlatformNodeMac::GetIndexInParent() {
   // TODO(dmazzoni): implement this.  http://crbug.com/396137
   return -1;
 }
 
 }  // namespace ui