Divide volume_manager.js into files for each classes and extract interfaces from them.

ui/file_manager/externs/volume_info_list.js

Index: ui/file_manager/externs/volume_info_list.js
diff --git a/ui/file_manager/externs/volume_info_list.js b/ui/file_manager/externs/volume_info_list.js
new file mode 100644
index 0000000000000000000000000000000000000000..3a5f1f7114a637b10c4098b17cc2faaec0a4c465
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+++ b/ui/file_manager/externs/volume_info_list.js
@@ -0,0 +1,76 @@
+// 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.
+
+/**
+ * The container of the VolumeInfo for each mounted volume.
+ * @interface
+ */
+function VolumeInfoList() {};
+
+/** @type {number} */
+VolumeInfoList.prototype.length;
+
+/**
+ * Adds the event listener to listen the change of volume info.
+ * @param {string} type The name of the event.
+ * @param {function(Event)} handler The handler for the event.
+ */
+VolumeInfoList.prototype.addEventListener = function(type, handler) {};
+
+/**
+ * Removes the event listener.
+ * @param {string} type The name of the event.
+ * @param {function(Event)} handler The handler to be removed.
+ */
+VolumeInfoList.prototype.removeEventListener = function(type, handler) {};
+
+/**
+ * Adds the volumeInfo to the appropriate position. If there already exists,
+ * just replaces it.
+ * @param {VolumeInfo} volumeInfo The information of the new volume.
+ */
+VolumeInfoList.prototype.add = function(volumeInfo) {};
+
+/**
+ * Removes the VolumeInfo having the given ID.
+ * @param {string} volumeId ID of the volume.
+ */
+VolumeInfoList.prototype.remove = function(volumeId) {};
+
+/**
+ * Obtains an index from the volume ID.
+ * @param {string} volumeId Volume ID.
+ * @return {number} Index of the volume.
+ */
+VolumeInfoList.prototype.findIndex = function(volumeId) {};
+
+/**
+ * Searches the information of the volume that contains the passed entry.
+ * @param {!Entry|!FakeEntry} entry Entry on the volume to be found.
+ * @return {VolumeInfo} The volume's information, or null if not found.
+ */
+VolumeInfoList.prototype.findByEntry = function(entry) {};
+
+/**
+ * Searches the information of the volume that exists on the given device path.
+ * @param {string} devicePath Path of the device to search.
+ * @return {VolumeInfo} The volume's information, or null if not found.
+ */
+VolumeInfoList.prototype.findByDevicePath = function(devicePath) {};
+
+/**
+ * Returns a promise that will be resolved when volume info, identified
+ * by {@code volumeId} is created.
+ *
+ * @param {string} volumeId
+ * @return {!Promise.<!VolumeInfo>} The VolumeInfo. Will not resolve
+ *     if the volume is never mounted.
+ */
+VolumeInfoList.prototype.whenVolumeInfoReady = function(volumeId) {};
+
+/**
+ * @param {number} index The index of the volume in the list.
+ * @return {!VolumeInfo} The VolumeInfo instance.
+ */
+VolumeInfoList.prototype.item = function(index) {};