SyncFS: use stored resource ID for the sync root instead of getting it each time

(i.e. this patch reverts http://crrev.com/187520)

BUG=178637
TEST=launch an app, move the sync root to somewhere by web I/F, reload the app, make sure a client still uses the moved sync root and does not create new one
TEST=make sure other new client creates and uses separate new sync root

Review URL: https://codereview.chromium.org/12834007
Patch from Hiroki Nakagawa <[email protected]>.

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@189664 0039d316-1c4b-4281-b951-d872f2087c98
5 files changed