[fsp] Add support for deleting entries.

chrome/renderer/resources/extensions/file_system_provider_custom_bindings.js

 // 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.
 
 // Custom binding for the fileSystemProvider API.
 
 var binding = require('binding').Binding.create('fileSystemProvider');
 var fileSystemProviderInternal =
     require('binding').Binding.create('fileSystemProviderInternal').generate();
 var eventBindings = require('event_bindings');
@@ skipping 186 matching lines @@
             options.fileSystemId, options.requestId, error,
             Date.now() - executionStart);
       }
       dispatch([options, onSuccessCallback, onErrorCallback]);
     });
 
 eventBindings.registerArgumentMassager(
     'fileSystemProvider.onCreateDirectoryRequested',
     massageArgumentsDefault);
 
+eventBindings.registerArgumentMassager(
+    'fileSystemProvider.onDeleteEntryRequested',
+    massageArgumentsDefault);
+
 exports.binding = binding.generate();