Revert of DevTools: rename initialUrl to url in the Browser.createTarget protocol method. (patchset #3 id:40001 of https://codereview.chromium.org/2140533003/ )

Reason for revert:
Broke a test.

Original issue's description:
> DevTools: rename initialUrl to url in the Browser.createTarget protocol method, fix chrome embedder handler.
>
> TBR=alexclarke
> NOTRY=true
> NOPRESUBMIT=true
>
> Committed: https://crrev.com/d3814a729f29e99cbdcbd470d2520cacb5ec4e53
> Cr-Commit-Position: refs/heads/master@{#404839}

TBR=paulirish@chromium.org,alexclarke@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review-Url: https://codereview.chromium.org/2143183003
Cr-Commit-Position: refs/heads/master@{#404843}
5 files changed