gdata: Add requestDirectoryRefresh to file_browser_private.

chrome/common/extensions/api/file_browser_private.json

Index: chrome/common/extensions/api/file_browser_private.json
diff --git a/chrome/common/extensions/api/file_browser_private.json b/chrome/common/extensions/api/file_browser_private.json
index 4e90de18324dd8fbd2ff7e6bb8a776315be8fc11..3b28fd858ec4762d822e0cb9e2591af64c7a31e3 100644
--- a/chrome/common/extensions/api/file_browser_private.json
+++ b/chrome/common/extensions/api/file_browser_private.json
@@ -932,6 +932,17 @@
             ]
           }
         ]
+      },
+      {
+        "name": "requestDirectoryRefresh",
+        "description": "Requests a refresh of a directory. Used to get the latest metadata of files in a particular directory. Upon completion, onFileChanged event is raised against the target directory, so that the file browser can redraw contents in the directory. Note that the onFileChanged event can be raised even if there is no change in the directory as it's expensive to check if the new contents match the existing ones.",
+        "parameters": [
+          {
+            "name": "fileURL",
+            "type": "string",
+            "description": "URL of the target directory"
+          }
+        ]
       }
     ],
     "events": [