Add script files of the separated Gallery.app.

ui/file_manager/gallery/js/background.js

+// 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.
+
+'use strict';
+
+var stringData = new Promise(function(fulfill) {
+  chrome.fileBrowserPrivate.getStrings(function(stringData) {
+    loadTimeData.data = stringData;
+    fulfill(stringData);
+  });
+});
+
+// VolumeManager should be obtained after stringData initialized.
+var volumeManager = stringData.then(function() {
+  return new Promise(function(fulfill) {
+    VolumeManager.getInstance(fulfill);
+  });
+});
+
+var backgroundComponent = Promise.all([stringData, volumeManager]).
+    then(function(args) {
+      return {
+        stringData: args[0],
+        volumeManager: args[1]
+      };
+    });
+
+chrome.app.runtime.onLaunched.addListener(function(launchData) {
+  // Skip if files are not selected.
+  if (!launchData || !launchData.items || launchData.items.length == 0)
+    return;
+
+  // Open application window.
+  chrome.app.window.create(
+      'gallery.html',
+      {
+        id: 'video',
+        minWidth: 160,
+        minHeight: 100,
+        frame: 'none'
+      },
+      function(appWindow) {
+        appWindow.contentWindow.launchData = launchData;
+        appWindow.contentWindow.backgroundComponent = backgroundComponent;
+      });
+});