Cleanup iOS upstreamed code

- remove unused consumer code wrapping base/ios/ios_util.h
- remove superfluous #include of base/ios/ios_util.h

BUG=429756
TBR=thakis

Review URL: https://codereview.chromium.org/940033003

Cr-Commit-Position: refs/heads/master@{#317054}
14 files changed