[FileBrowser] Added DefaultAction dialog to choose default action.

chrome/common/extensions/api/file_browser_private.json

 // Copyright (c) 2012 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.
 
 [
   {
     "namespace":"fileBrowserPrivate",
     "nodoc": "true",
     "types": [
       {
@@ skipping 370 matching lines @@
                 "name": "success",
                 "type": "boolean",
                 "optional": true,
                 "description": "True of task execution was successfully initiated."
               }
             ]
           }
         ]
       },
       {
+        "name": "setDefaultTask",
+        "description": "Sets default task.",
+        "parameters": [
+          {
+            "name": "taskId",
+            "type": "string",
+            "description": "The unique identifier of task to mark as default."
+          },
+          {
+            "name": "callback",
+            "type": "function",
+            "optional": true,
+            "parameters": []
+          }
+        ]        
+      },
+      {
         "name": "getFileTasks",
         "description": "Gets the list of tasks that can be performed over selected files.",
         "parameters": [
           {
             "name": "fileURLs",
             "type": "array",
             "description": "Array of selected file URLs",
             "items": { "type": "string" }
           },
           {
@@ skipping 614 matching lines @@
       },
       {
         "name": "onNetworkConnectionChanged",
         "type": "function",
         "description": "Fired when the active network connection state changes. The network connection state can be retrieved via 'getNetworkConnectionState'.",
         "parameters": []
       }
     ]
   }
 ]