drive: Pass through AboutResouce from server amond callbacks in ChangeListLoader.
This help us refactoring the pseudo tree structure with separate namespaces.
We would like to create a dummy "My Drive" root in ChangeListProcessor and use
it as "drive/root" instead of having it in DriveResourceMetadata.
This operation needs the root folder ID.
It also helps our migration to Drive API.
BUG=174233
TEST=unittests. Open Files App and verify Google Drive is available.
Review URL: https://chromiumcodereview.appspot.com/12588009
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@189323 0039d316-1c4b-4281-b951-d872f2087c98
8 files changed
