Revert of Start EmbeddedWorker during registration - take 2

Revert of Start EmbeddedWorker during registration - take 2 (https://codereview.chromium.org/140743012/)

Reason for revert:
Makes virtual/serviceworker/http/tests/serviceworker/registration.html crash.
See http://build.chromium.org/p/chromium.webkit/builders/WebKit%20Linux/builds/26615

Original issue's description:
> Start EmbeddedWorker during registration - take 2
> 
> This adds the starting of the server worker to the registration
> job pipeline. Eventually this will also dispatch the 'install'
> event.
> 
> A second version of this, based on kinuko's work
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=249544

TBR=kinuko@chromium.org,alecflett@chromium.org
NOTREECHECKS=true
NOTRY=true

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=249674

[alph, 2014-02-07 11:44:35]

Created Revert of Start EmbeddedWorker during registration - take 2

[commit-bot: I haz the power, 2014-02-07 11:44:54]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/alph@chromium.org/137233019/1

[commit-bot: I haz the power, 2014-02-07 11:45:13]

Change committed as 249674

[kinuko, 2014-02-07 11:51:27]

Whoa, didn't really remember we had a layouttests for SW... thanks.