Fix accessibility issues in AudioPlayer and VideoPlayer.

ui/file_manager/file_manager/foreground/elements/files_icon_button.js

Index: ui/file_manager/file_manager/foreground/elements/files_icon_button.js
diff --git a/ui/file_manager/file_manager/foreground/elements/files_icon_button.js b/ui/file_manager/file_manager/foreground/elements/files_icon_button.js
new file mode 100644
index 0000000000000000000000000000000000000000..63039f3c6971b300f894724c354d789fbcff2ae5
--- /dev/null
+++ b/ui/file_manager/file_manager/foreground/elements/files_icon_button.js
@@ -0,0 +1,29 @@
+// Copyright 2015 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.
+
+Polymer({
+  is: 'files-icon-button',
+
+  hostAttributes: {
+    role: 'button',
+    tabindex: 0
+  },
+
+  behaviors: [
+    Polymer.IronButtonState,
+    Polymer.IronControlState
+  ],
+
+  observers: [
+    '_focusedChanged(receivedFocusFromKeyboard)'
+  ],
+
+  _focusedChanged: function(receivedFocusFromKeyboard) {
+    if (receivedFocusFromKeyboard) {
+      this.classList.add('keyboard-focus');
+    } else {
+      this.classList.remove('keyboard-focus');
+    }
+  }
+});