MacViews: Implement Full Keyboard Access.

ui/views/focus/focus_search_mac.mm

+// Copyright 2016 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/views/focus/focus_search.h"
+
+#import <Cocoa/Cocoa.h>
+
+#include "ui/views/view.h"
+
+namespace views {
+
+bool FocusSearch::IsFocusable(View* v) {
+  // Use the accessibility mode, if full keyboard access is enabled on Mac.
+  if (accessibility_mode_ || [NSApp isFullKeyboardAccessEnabled]) {
+    return v && v->IsAccessibilityFocusable();
+  }
+  return v && v->IsFocusable();
+}
+
+}  // namespace views