Initialize WakeLockContextHost lazily

Initialize WakeLockContextHost lazily

Most WebContents instances won't need it.

BUG=689403
TEST=On Chrome on Android, go to about://flags and turn on "Experimental Web
Platform features." Restart Chrome. Go to
https://colinblundell.github.io/wake_lock.html and verify that the page
says "Wake Lock API found". Verify that if you wait ~40 seconds, the device
goes to sleep. Tap "Block sleep." Verify that if you wait longer than the
above period, the device does not go to sleep. Tap "Unblock sleep" and
verify again that the device goes to sleep after waiting.

Review-Url: https://codereview.chromium.org/2777143002
Cr-Commit-Position: refs/heads/master@{#460035}
Committed: https://chromium.googlesource.com/chromium/src/+/d8cd72b77ad75432b531dd5d2c5d866544a2240c

[blundell, 2017-03-27 13:27:43]

The CQ bit was checked by blundell@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-03-27 13:27:54]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[blundell, 2017-03-27 14:23:38]

blundell@chromium.org changed reviewers:
+ jam@chromium.org

[commit-bot: I haz the power, 2017-03-27 14:24:29]

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

[commit-bot: I haz the power, 2017-03-27 14:24:30]

Dry run: This issue passed the CQ dry run.

[jam, 2017-03-27 20:01:54]

lgtm

[blundell, 2017-03-28 07:13:12]

The CQ bit was checked by blundell@chromium.org

[commit-bot: I haz the power, 2017-03-28 07:13:30]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-03-28 07:18:43]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1490685192427350, "parent_rev":
"80b4756199415114359a26ae94c7dbf91d17bd2b", "commit_rev":
"d8cd72b77ad75432b531dd5d2c5d866544a2240c"}

[commit-bot: I haz the power, 2017-03-28 07:19:26]

Description was changed from

==========
Initialize WakeLockContextHost lazily

Most WebContents instances won't need it.

BUG=689403
TEST=On Chrome on Android, go to about://flags and turn on "Experimental Web
Platform features." Restart Chrome. Go to
https://colinblundell.github.io/wake_lock.html and verify that the page
says "Wake Lock API found". Verify that if you wait ~40 seconds, the device
goes to sleep. Tap "Block sleep." Verify that if you wait longer than the
above period, the device does not go to sleep. Tap "Unblock sleep" and
verify again that the device goes to sleep after waiting.
==========

to

==========
Initialize WakeLockContextHost lazily

Most WebContents instances won't need it.

BUG=689403
TEST=On Chrome on Android, go to about://flags and turn on "Experimental Web
Platform features." Restart Chrome. Go to
https://colinblundell.github.io/wake_lock.html and verify that the page
says "Wake Lock API found". Verify that if you wait ~40 seconds, the device
goes to sleep. Tap "Block sleep." Verify that if you wait longer than the
above period, the device does not go to sleep. Tap "Unblock sleep" and
verify again that the device goes to sleep after waiting.

Review-Url: https://codereview.chromium.org/2777143002
Cr-Commit-Position: refs/heads/master@{#460035}
Committed:
https://chromium.googlesource.com/chromium/src/+/d8cd72b77ad75432b531dd5d2c5d...
==========

[commit-bot: I haz the power, 2017-03-28 07:19:27]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/d8cd72b77ad75432b531dd5d2c5d...