downloads: break downloads.js into more classes/files.

chrome/browser/resources/downloads/compiled_resources.gyp

 # 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.
 {
   'targets': [
     {
-      'target_name': 'downloads',
+      'target_name': 'manager',
       'variables': {
         'depends': [
           '../../../../ui/webui/resources/js/action_link.js',
           '../../../../ui/webui/resources/js/assert.js',
           '../../../../ui/webui/resources/js/compiled_resources.gyp:load_time_data',
           '../../../../ui/webui/resources/js/cr.js',
           '../../../../ui/webui/resources/js/cr/ui.js',
           '../../../../ui/webui/resources/js/cr/ui/command.js',
           '../../../../ui/webui/resources/js/cr/ui/focus_grid.js',
           '../../../../ui/webui/resources/js/cr/ui/focus_row.js',
           '../../../../ui/webui/resources/js/event_tracker.js',
           '../../../../ui/webui/resources/js/util.js',
+          'item.js',
+          'item_view.js',
+          'focus_row.js',
         ],
-        'externs': ['<(CLOSURE_DIR)/externs/chrome_send_externs.js'],
+        'externs': [
+          '<(CLOSURE_DIR)/externs/chrome_send_externs.js',
+          'externs.js',
+        ],
       },
       'includes': ['../../../../third_party/closure_compiler/compile_js.gypi'],
     }
   ],
 }