This patch includes following fix in classifierHelper.js:
1. Avoid the reuse of same chunk numbers
2. Remove unused removeUrlFromDB function
MozReview-Commit-ID: XK1oHBa8gf
resetDatabase() is used to clear out the Safe Browsing database and cache in tests.
Since bug 1333328 however we can no longer rely on updates clearing the cache.
There are two solutions to address this issue:
1. resetDatabase() calls another test-only function: reloadDatabase(). Since the cache
is in memory, reloading the URL classifier will automatically clear the cache.
2. During an update, remove cache entries which are not in the database.
I prefer taking the first one because if we implement the second
approach, an update will take longer since we need to check if each prefix
in the cache can also be found in the database. I think this is not necessary
because prefixes not in the database will eventually be removed when they
are expired.
MozReview-Commit-ID: BjsDKDMr205
