[fsp] Add support for opening files.

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 143 matching lines @@
             fileSystemId, requestId, annotatedEntries, hasNext);
       };
       var onErrorCallback = function(error) {
         fileSystemProviderInternal.readDirectoryRequestedError(
             fileSystemId, requestId, error);
       }
       dispatch([
           fileSystemId, directoryPath, onSuccessCallback, onErrorCallback]);
     });
 
+eventBindings.registerArgumentMassager(
+    'fileSystemProvider.onOpenFileRequested',
+    function(args, dispatch) {
+      var fileSystemId = args[0];
+      var requestId = args[1];
+      var filePath = args[2];
+      var mode = args[3];
+      var create = args[4];
+      var onSuccessCallback = function() {
+        fileSystemProviderInternal.openFileRequestedSuccess(
+            fileSystemId, requestId);
+      };
+      var onErrorCallback = function(error) {
+        fileSystemProviderInternal.openFileRequestedError(
+          fileSystemId, requestId, error);
+      }
+      dispatch([fileSystemId, filePath, mode, create, onSuccessCallback,
+                onErrorCallback]);
+    });
+
 exports.binding = binding.generate();