ServiceWorker: Resubmit worker script MIME type fix.

ServiceWorker: Resubmit worker script MIME type fix.

This is a re-submission of https://codereview.chromium.org/446323002/.
Fixed the new browsertest which intercept worker script request but returns
response without corret worker content type.

BUG=400604
TEST=https://codereview.chromium.org/448063002/

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=289238

[xiang, 2014-08-12 08:50:09]

PTAL, thanks!

[falken, 2014-08-12 09:16:16]

On 2014/08/12 08:50:09, xiang wrote:
> PTAL, thanks!

Since the only change from the last CL is one line in
content/browser/service_worker/service_worker_browsertest.cc, lgtm

[Lei Zhang, 2014-08-12 19:08:08]

chrome/ still lgtm

[michaeln, 2014-08-12 19:09:11]

still lgtm2

[xiang, 2014-08-13 00:34:37]

The CQ bit was checked by xiang.long@intel.com

[commit-bot: I haz the power, 2014-08-13 00:46:53]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/xiang.long@intel.com/460943002/1

[commit-bot: I haz the power, 2014-08-13 04:16:51]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  win_chromium_x64_rel on tryserver.chromium.win
(http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_x64_...)

[xiang, 2014-08-13 06:48:05]

The CQ bit was unchecked by xiang.long@intel.com

[xiang, 2014-08-13 06:48:19]

The CQ bit was checked by xiang.long@intel.com

[commit-bot: I haz the power, 2014-08-13 06:48:34]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/xiang.long@intel.com/460943002/1

[commit-bot: I haz the power, 2014-08-13 09:49:44]

Change committed as 289238