Eliminate the archived history database and clean up related code.
More specifically, this change list:
* Removes all code related to the archived history database, and removes all mentions of it from comments.
* Adds some code to purge the legacy database file on disk on first start-up, plus a unit test to check that this works.
* Removes a migration path from M17 which was responsible for migrating some components, all of which have been unimplemented since then, except for the archived database, which, however, is now being removed.
* Removes a tiny amount of code and some mentions of a "supplementary URL index" on the URLs table (this was unimplemented a long time ago). This is needed because otherwise some updated comments would be confusing.
BUG=359377
TBR=pkasting@chromium.org
Review URL: https://codereview.chromium.org/235863023
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@275159 0039d316-1c4b-4281-b951-d872f2087c98
25 files changed
