Disable zip selection on MTP volume.

BUG=486397
TEST=manually tested; Right click a folder on MTP volume, and confirmed that zip selection is disabled.

Review URL: https://codereview.chromium.org/1138973002

Cr-Commit-Position: refs/heads/master@{#329626}

ui/file_manager/file_manager/foreground/js/directory_model.js

@@ -179,13 +179,29 @@ DirectoryModel.prototype.isSearching = function() {
 };
 
 /**
- * @return {boolean}
+ * @return {boolean} True if it's on Drive.
  */
 DirectoryModel.prototype.isOnDrive = function() {
+  return this.isCurrentRootVolumeType_(VolumeManagerCommon.VolumeType.DRIVE);
+};
+
+/**
+ * @return {boolean} True if it's on MTP volume.
+ */
+DirectoryModel.prototype.isOnMTP = function() {
+  return this.isCurrentRootVolumeType_(VolumeManagerCommon.VolumeType.MTP);
+};
+
+/**
+ * @param {VolumeManagerCommon.VolumeType} volumeType Volume Type
+ * @return {boolean} True if current root volume type is equal to specified
+ *     volume type.
+ * @private
+ */
+DirectoryModel.prototype.isCurrentRootVolumeType_ = function(volumeType) {
   var rootType = this.getCurrentRootType();
   return rootType != null &&
-      VolumeManagerCommon.getVolumeTypeFromRootType(rootType) ==
-      VolumeManagerCommon.VolumeType.DRIVE;
+      VolumeManagerCommon.getVolumeTypeFromRootType(rootType) === volumeType;
 };
 
 /**

ui/file_manager/file_manager/foreground/js/file_manager.js

@@ -1253,6 +1253,13 @@ FileManager.prototype = /** @struct */ {
     return this.directoryModel_.isOnDrive();
   };
 
+  /**
+   * @return {boolean} True if the current directory content is from MTP volume.
+   */
+  FileManager.prototype.isOnMTP = function() {
+    return this.directoryModel_.isOnMTP();
+  };
+
   /**
    * Check if the drive-related setting items should be shown on currently
    * displayed gear menu.

ui/file_manager/file_manager/foreground/js/file_manager_commands.js

@@ -1024,6 +1024,7 @@ CommandHandler.COMMANDS_['zip-selection'] = /** @type {Command} */ ({
         dirEntry &&
         !fileManager.isOnReadonlyDirectory() &&
         !fileManager.isOnDrive() &&
+        !fileManager.isOnMTP() &&
         selection && selection.totalCount > 0;
   }
 });