Implement the 'noopener' link relation.

Implement the 'noopener' link relation.

Intent to Implement and Ship: https://groups.google.com/a/chromium.org/d/msg/blink-dev/hqW3RGDV8WI/bGe64uK-AQAJ

BUG=551884
Committed: https://crrev.com/a807c1ad89f79e2f98c068ad7fee1cdf23a6f1fd
Cr-Commit-Position: refs/heads/master@{#359852}

[Mike West, 2015-11-13 16:12:54]

mkwst@chromium.org changed reviewers:
+ jochen@chromium.org

[Mike West, 2015-11-13 16:12:55]

Would you mind taking a look at this, Jochen? Intent to Ship is in the CL
description. I'll wait on this until that thread resolves, but I'd appreciate
you taking a look anyway. I basically copied the browser tests for `noreferrer`,
since I plan on killing the hacks that allow `noreferrer` tests to work
correctly in Blink (they rely on `window.name`-based targeting, which shouldn't
work).

WDYT?

[Mike West, 2015-11-15 08:17:39]

https://codereview.chromium.org/1443663003/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/html/HTMLAnchorElement.h (right):

https://codereview.chromium.org/1443663003/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/html/HTMLAnchorElement.h:57: RelationNoOpener =
0x00040000,
`git cl format`.

[Mike West, 2015-11-16 09:28:18]

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

[commit-bot: I haz the power, 2015-11-16 09:28:24]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1443663003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1443663003/20001

[commit-bot: I haz the power, 2015-11-16 10:52:50]

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

[commit-bot: I haz the power, 2015-11-16 10:52:50]

Dry run: This issue passed the CQ dry run.

[jochen (gone - plz use gerrit), 2015-11-16 12:01:28]

lgtm

[Mike West, 2015-11-16 16:18:25]

The CQ bit was checked by mkwst@chromium.org

[commit-bot: I haz the power, 2015-11-16 16:18:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1443663003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1443663003/20001

[commit-bot: I haz the power, 2015-11-16 16:23:03]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-11-16 16:24:21]

Patchset 2 (id:??) landed as
https://crrev.com/a807c1ad89f79e2f98c068ad7fee1cdf23a6f1fd
Cr-Commit-Position: refs/heads/master@{#359852}