GitLab

Removes the migration code to history DB version 34. This version did a
large migration of the URL table which can use several MB of disk storage. The
suspicion is that this is causing more initialization failures for users with
full devices.

The change in version 34 is to add an AUTOINCREMENT tag on the primary key.
This is required for some sync work that is in progress but is not complete,
so skipping this migration step won't break any users. We will need to fix
this before rolling out the new sync features.

The 34 change also removed the favicon_id column. Because some databases
may have the column and some won't, the code to copy to the in-memory
database (which previously was implicit) now lists the columns to copy
explicitly.

Adds UMA logging for history database initialization failures, as well as
versions for migration failures. Logging for the Sqlite error code for the
various failure states may have been nice but would have required more
plumbing and seemed impractical for now.

There is one behavior change the error logging resulted in: errors migrating
to version 22 were previously ignored but are now fatal. I believe continuing
in this case was a mistake. This will only affect users migrating from an
Android Chrome version prior to 2012, and failures here will likely be fatal
anyway.

BUG=734194, 736136
R=dtrainor@chromium.org, gangwu@chromium.org, mpearson@chromium.org, yzshen@chromium.org

Review-Url: https://codereview.chromium.org/2954593002 .
Cr-Commit-Position: refs/heads/master@{#481958}