Remove some legacy versions of StartsWith and EndsWith.

This just replaces
  true -> base::CompareCase::SENSITIVE
  false -> base::CompareCase::INSENSITIVE_ASCII

I checked the insensitive cases to make sure they're not doing anything suspicious. The old version is a sometimes-correct Unicode comparison so converting to INSENSTITIVE_ASCII isn't a no-op. However, generally the prefix/suffix checking is done against a hardcoded string so there were very few cases to actually look at.

extensions/browser/api/declarative_webrequest/webrequest_condition_attribute.cc has a not-quite search-and-replace change where I changed the type of a class variable.

BUG=506255
TBR=jam

Reland of http://crrev.com/1239493005

Review URL: https://codereview.chromium.org/1233043003

Cr-Original-Commit-Position: refs/heads/master@{#339071}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: a7ff1b291cd328e9584779a4bb9101fa9a3c01ad