Add a has_media flag to VolumeMetadata.

chrome/common/extensions/api/file_manager_private.idl

 // Copyright 2013 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.
 
 // fileManagerPrivate API.
 // This is a private API used by the file browser of ChromeOS.
 [platforms=("chromeos"),
  implemented_in="chrome/browser/chromeos/extensions/file_manager/file_manager_private_api_functions.h"]
 namespace fileManagerPrivate {
 // Type of the mounted volume.
@@ skipping 261 matching lines @@
   // Path to identify the device. This is consistent with DeviceEvent's
   // devicePath.
   DOMString? devicePath;
 
   // Whether the device is parent or not (i.e. sdb rather than sdb1).
   boolean? isParentDevice;
 
   // Flag that specifies if volume is mounted in read-only mode.
   boolean isReadOnly;
 
+  // Flag that specifies whether the volume contains media.

[Steve McKay, 2014/10/22 02:16:00]

So what this is doing is exposing an existing "hasMedia" attribute? What's the
underlying heuristic for identifying media?

+  boolean hasMedia;
+  
   // Additional data about mount, for example, that the filesystem is not
   // supported.
   MountCondition? mountCondition;
 };
 
 // Payload data for mount event.
 dictionary MountCompletedEvent {
   // Is the event raised for mounting or unmounting.
   MountCompletedEventType eventType;
 
@@ skipping 511 matching lines @@
 
   static void onPreferencesChanged();
 
   static void onDriveConnectionStatusChanged();
 
   static void onDeviceChanged(DeviceEvent event);
 
   static void onDriveSyncError(DriveSyncErrorEvent event);
 };
 };