Make navigator.serviceWorker.ready resolve with the controller.

Make navigator.serviceWorker.ready resolve with the controller.

The specification for ready is here:
https://github.com/slightlyoff/ServiceWorker/issues/223

ready is a convenience that lets the page talk to an installed
ServiceWorker, without having to track the details of whether that
Service Worker is controlling the page, or merely installed but
waiting for the page to reload.

This implements the trivial ready case, where the page is
controlled by a Service Worker and ready can produce that one
immediately.

BUG=363967
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=175486

[dominicc (has gone to gerrit), 2014-06-03 06:35:45]

PTAL

This relies on https://codereview.chromium.org/309503014/ going first so that ==
used by the test works.

This implements one of the trivial whenReady cases, where the document is
already controlled by a Service Worker. After the waiting property is
implemented and wired up, delayed whenReady resolution will also be possible.
The plan is to have the WebCore::ServiceWorkerContainer maintain that state
purely in Blink.

[michaeln, 2014-06-03 23:35:55]

lgtm

fyi, there's discussion about changing the method to a property, please see
github.

[dominicc (has gone to gerrit), 2014-06-04 00:58:57]

The CQ bit was checked by dominicc@chromium.org

[commit-bot: I haz the power, 2014-06-04 00:59:33]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/dominicc@chromium.org/309233002/20001

[dominicc (has gone to gerrit), 2014-06-04 01:57:15]

The CQ bit was checked by dominicc@chromium.org

[commit-bot: I haz the power, 2014-06-04 01:57:35]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/dominicc@chromium.org/309233002/40001

[commit-bot: I haz the power, 2014-06-04 03:23:11]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  linux_blink_dbg on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/linux_blink_dbg/builds/1...)
  mac_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/mac_blink_rel/builds/10184)
  win_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/win_blink_rel/builds/10505)

[commit-bot: I haz the power, 2014-06-04 03:26:10]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-06-04 03:26:11]

Try jobs failed on following builders:
  linux_blink_dbg on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/linux_blink_dbg/builds/1...)

[dominicc (has gone to gerrit), 2014-06-04 12:09:54]

The CQ bit was checked by dominicc@chromium.org

[commit-bot: I haz the power, 2014-06-04 12:10:50]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/dominicc@chromium.org/309233002/40001

[commit-bot: I haz the power, 2014-06-04 13:05:26]

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

[commit-bot: I haz the power, 2014-06-04 14:27:08]

Change committed as 175486