drive: Update parent entry first when appropriate

EntryUpdatePerformer does nothing if the parent is a locally created entry waiting for update.
SyncClient adds update tasks for child entries.
Add ResourceMetadata::ReadDirectoryById

BUG=260540
TEST=unit_tests
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Review URL: https://codereview.chromium.org/151203004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248441 0039d316-1c4b-4281-b951-d872f2087c98
6 files changed