Files app: Move common/js/externs.js to externs/*.

ui/file_manager/externs/directory_change_event.js

-// Copyright 2014 The Chromium Authors. All rights reserved.
+// 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.
 
-// TODO(yawano): Move all externs under ui/file_manager/externs.
-
-/**
- * @constructor
- * @extends {Window}
- */
-var BackgroundWindow = function() {};
-
-/**
- * @type {FileBrowserBackground}
- */
-BackgroundWindow.prototype.background;
-
-/**
- * @param {Window} window
- */
-BackgroundWindow.prototype.registerDialog = function(window) {};
-
-/**
- * @param {Object=} opt_appState App state.
- * @param {number=} opt_id Window id.
- * @param {LaunchType=} opt_type Launch type. Default: ALWAYS_CREATE.
- * @param {function(string)=} opt_callback Completion callback with the App ID.
- */
-BackgroundWindow.prototype.launchFileManager =
-    function(opt_appState, opt_id, opt_type, opt_callback) {};
-
-
 /**
  * @constructor
  * @extends {Event}
- */
-var FileOperationProgressEvent = function() {};
-
-/** @type {fileOperationUtil.EventRouter.EventType} */
-FileOperationProgressEvent.prototype.reason;
-
-/** @type {(fileOperationUtil.Error|undefined)} */
-FileOperationProgressEvent.prototype.error;
-
-
-/**
- * @constructor
- * @extends {Event}
- */
-var EntriesChangedEvent = function() {};
-
-/** @type {util.EntryChangedKind} */
-EntriesChangedEvent.prototype.kind;
-
-/** @type {Array<!Entry>} */
-EntriesChangedEvent.prototype.entries;
-
-/**
- * @constructor
- * @extends {Event}
  * @struct
  */
 var DirectoryChangeEvent = function() {};
 
 /** @type {DirectoryEntry} */
 DirectoryChangeEvent.prototype.previousDirEntry;
 
 /** @type {DirectoryEntry|FakeEntry} */
 DirectoryChangeEvent.prototype.newDirEntry;
 
 /** @type {boolean} */
-DirectoryChangeEvent.prototype.volumeChanged;
+DirectoryChangeEvent.prototype.volumeChanged;