Revert 270016 "Add most of the metadata-handling code for blobs...."

This may have caused indexed_db layout tests to start failing.

> Add most of the metadata-handling code for blobs.  It's not quite all there, but
> this is the biggest chunk I can pull out vaguely cleanly.  It does contain a
> couple of fake calls to keep the compiler happy.
> This CL also makes SetUpMetadata a member in order to ease testing in a later CL.
> 
> This depends on https://codereview.chromium.org/261843004/.
> 
> BUG=108012
> 
> Review URL: https://codereview.chromium.org/266333002

TBR=ericu@chromium.org

Review URL: https://codereview.chromium.org/281623004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@270038 0039d316-1c4b-4281-b951-d872f2087c98
3 files changed