Revert "Ensure we properly set PageTransition for iframes."

This reverts commit 735aa03be45990a5e2feb3c38087e6f76eb920ac AKA refs/heads/master@{#326404}
Reverting because it caused a bug which is currently the top crasher on canary.

Original description: Ensure we properly set PageTransition for iframes.
 We currently don't set subframe navigations as manual when it isn't the first
 navigation of the iframe. Also, we don't propagate the state correctly in the
 case of a cross-process transition.

 Original Review URL: https://codereview.chromium.org/1002953004

 Original Cr-Commit-Position: refs/heads/master@{#326404}

TBR=creis@chromium.org, japhet@chromium.org
BUG=464014,480839

Review URL: https://codereview.chromium.org/1108863002

Cr-Commit-Position: refs/heads/master@{#327100}
9 files changed