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..18832aa796cc2cc18abc408cab89c3dfabcd8ff0 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.",

[asargent_no_longer_on_chrome, 2012/05/18 23:22:34]

Does onFileChanged fire even if the item at |fileURL| actually didn't change?
Also, since this is a directory, should the caller expect to potentially see
onFileChanged fire for any of the files within that directory and its
subdirectories? If so will those fire before or after the onFileChanged for the
directory itself?

BTW, if you're really just interested in giving callers a way to know when
requestDirectoryRefresh has finished some async work in the browser process, you
can declare this to have a no-parameter callback and make its c++ implementation
in the browser process inherit from AsyncExtensionFunction and wait to call
SendResponse once the refresh is complete. 

Then callers in js can do:

chrome.fileBrowserPrivate.requestDirectoryRefresh(
    myurl, function() {
  console.log("directory refresh complete!");
});

[satorux1, 2012/05/18 23:42:19]

Thank you for the suggestion. I thought that notifying the completion via the
existing onFileChanged event was simpler, but now I think it's rather dirty. I'm
going to rework the patch and add ad no-parameter callback.

[satorux1, 2012/05/19 00:09:19]

I played with the new idea, but I changed my mind again. If the contents in the
directory are changed, it's natural to raise onFileChanged() event against the
target directory. If so, notifying the completion via the non-parameter callback
is redundant.

So I kept the API as-is, but added more comments about the semantics.

+        "parameters": [
+          {
+            "name": "fileURL",
+            "type": "string",
+            "description": "URL of the target directory"
+          }
+        ]
       }
     ],
     "events": [