IndexedDB: Create IDBTransaction interface

This CL creates a bare IDBTransaction interface with just the
CreateObjectStore method.  Later CLs will be responsible for
moving the remaining methods from IDBDatabase to IDBTransaction.

Bug: 717812
Change-Id: Ie1e084957e66f2afef563d37af9243726e48855b
Reviewed-by: Kinuko Yasuda <>
Reviewed-by: Tom Sepez <>
Reviewed-by: Daniel Murphy <>
Commit-Queue: Chase Phillips <>
Cr-Commit-Position: refs/heads/master@{#643406}
38 files changed