Don't set the origin twice when navigating for javascript: URLs

As javascript: navigations will end up with a document that has the
original document's URL, we shouldn't run the algorithm to determine
origin on the original URL, especially since we'll override the origin
later anyways.

BUG=583445
R=japhet@chromium.org,dcheng@chromium.org,mkwst@chromium.org

Review URL: https://codereview.chromium.org/1670173002

Cr-Commit-Position: refs/heads/master@{#373917}
7 files changed