Compile several targets in Gallery in gyp v2.

ui/file_manager/gallery/js/gallery_item_unittest.js

 // 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.
 
 /**
- * Mock of ImageUtil.
+ * Mock of ImageUtil and metrics.
  */
 var ImageUtil = {
   getMetricName: function() {},
-  metrics: {
-    recordEnum: function() {},
-    recordInterval: function() {},
-    startInterval: function() {}
-  }
+};
+var metrics = {
+  recordEnum: function() {},
+  recordInterval: function() {},
+  startInterval: function() {}
 };
 
 /**
  * Mock of ImageEncoder. Since some test changes the behavior of ImageEncoder,
  * this is initialized in setUp().
  */
 var ImageEncoder;
 
 /**
  * Load time data.
@@ skipping 276 matching lines @@
   // Jpeg file on non-writable volume.
   assertFalse(getGalleryItem(
       '/test.jpg', removable, true /* read only */).
       isWritableFile(volumeManager));
 
   // Jpeg file on mtp volume.
   assertFalse(getGalleryItem(
       '/test.jpg', mtp, false /* not read only */).
       isWritableFile(volumeManager));
 };