This is the master CL that contains the whole remaining Blink side.  It turns on Blob support in IDB, so it has to wait until the Chromium side has completely landed.

See https://codereview.chromium.org/18023022/ for the Chromium side.
See https://docs.google.com/a/chromium.org/document/d/1Kdr4pcFt4QBDLLQn-fY4kZgw6ptmK23lthGZdQMVh2Y/edit for the big picture document [chromium.org account required].
Read-only view at https://docs.google.com/document/d/1Kdr4pcFt4QBDLLQn-fY4kZgw6ptmK23lthGZdQMVh2Y/pub [no account required].

BUG=108012

Review URL: https://codereview.chromium.org/18590006

git-svn-id: svn://svn.chromium.org/blink/trunk@175802 bbb929c8-8fbe-4397-9dbb-9b2b20218538