Revert 113823 - net: move pinning checks into the SSL socket.

Revert 113823 - net: move pinning checks into the SSL socket.

Previously we would reject requests with pinning errors at the URLRequest layer
but, by that time, we would already have sent cookies.

The commenting of the #ifdef is deliberate - it allows the builders to chew the
code over. Once the builders are happy I'll land another change to uncomment
the #ifdefs.

This also happens to start unpicking the DNS certificate provenance stuff.

BUG=none
TEST=Verify that https://pinningtest.appspot.com fails to load in offical builds.

Review URL: http://codereview.chromium.org/8865006

TBR=agl@chromium.org
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=113846