Returning sourcePath from chrome.fileBrowserPrivate.addMount for gdata.

chrome/browser/chromeos/extensions/file_browser_private_api.cc

Index: chrome/browser/chromeos/extensions/file_browser_private_api.cc
diff --git a/chrome/browser/chromeos/extensions/file_browser_private_api.cc b/chrome/browser/chromeos/extensions/file_browser_private_api.cc
index dc6ab4871c9f2a1a5f129f937cc13919d2c4a800..0d018fea5c840107bc68fbeb2eb4c8dd687fda83 100644
--- a/chrome/browser/chromeos/extensions/file_browser_private_api.cc
+++ b/chrome/browser/chromeos/extensions/file_browser_private_api.cc
@@ -1087,6 +1087,10 @@ bool AddMountFunction::RunImpl() {
     }
     case chromeos::MOUNT_TYPE_GDATA: {
       const bool success = true;
+      // Pass back the gdata mount point path as source path.
+      const std::string& gdata_path =
+          gdata::util::GetGDataMountPointPathAsString();
+      SetResult(Value::CreateStringValue(gdata_path));
       FileBrowserEventRouterFactory::GetForProfile(profile_)->
           MountDrive(base::Bind(&AddMountFunction::SendResponse,
                                 this,