Track which IndexedDBBackingStores have been opened since boot.
This way we'll know which need to have their live blob journals cleaned, once
blob support is in.

This has a small overlap with https://codereview.chromium.org/240003011/ [currently in the commit queue] for ease of merging.  However, it also fixes a bug in that CL in which GetDatabaseNames didn't have the request_context parameter.

BUG=108012

Review URL: https://codereview.chromium.org/259063004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@267031 0039d316-1c4b-4281-b951-d872f2087c98
7 files changed