Replace mountType by volumeType on fileBrowserPrivate APIs.

chrome/test/data/extensions/api_test/filebrowser_mount/test.js

Index: chrome/test/data/extensions/api_test/filebrowser_mount/test.js
diff --git a/chrome/test/data/extensions/api_test/filebrowser_mount/test.js b/chrome/test/data/extensions/api_test/filebrowser_mount/test.js
index 41818cf39e3e99fd5694827d12d89e76c4ddbdb7..c3ca27deb3da744b22b54bcdb4e2b2017e412619 100644
--- a/chrome/test/data/extensions/api_test/filebrowser_mount/test.js
+++ b/chrome/test/data/extensions/api_test/filebrowser_mount/test.js
@@ -59,30 +59,31 @@ var expectedDownloadsVolume = {
 var expectedMountPoints = [
   {
     mountPath: 'Downloads',
+    volumeType: 'downloads',
     mountCondition: ''
   },
   {
     sourcePath: 'archive_path',
     mountPath: 'archive/archive_mount_path',
-    mountType: 'file',
+    volumeType: 'archive',
     mountCondition: ''
   },
   {
     sourcePath: 'device_path1',
     mountPath: 'removable/mount_path1',
-    mountType: 'device',
+    volumeType: 'removable',
     mountCondition: ''
   },
   {
     sourcePath: 'device_path2',
     mountPath: 'removable/mount_path2',
-    mountType: 'device',
+    volumeType: 'removable',
     mountCondition: ''
   },
   {
     sourcePath: 'device_path3',
     mountPath: 'removable/mount_path3',
-    mountType: 'device',
+    volumeType: 'removable',
     mountCondition: ''
   }
 ];