[ios] Updates ios DEPS files to mirror desktop DEPS files.

Updates ios DEPS files to mirror the desktop DEPS files.  For example, the rules
in ios/DEPS roughly resemble the rules in DEPS, and the rules in ios/chrome/DEPS
roughly resemble the rules in chrome/DEPS.

Also adds some new rules to accomodate iOS code that will be landing in the near
future.

BUG=665969

Review-Url: https://codereview.chromium.org/2541083002
Cr-Commit-Position: refs/heads/master@{#436313}
4 files changed