Remove the redundant HTMLDocument.compatMode

Remove the redundant HTMLDocument.compatMode

Since Document.compatMode is defined identically and the implementation
is in Document::compatMode(), the only consequence of this is that the
compatMode attribute goes away from the HTMLDocument prototype.

BUG=460722
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=196624

[philipj_slow, 2015-06-05 23:02:23]

The CQ bit was checked by philipj@opera.com to run a CQ dry run

[commit-bot: I haz the power, 2015-06-05 23:02:36]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1164533007/1

[commit-bot: I haz the power, 2015-06-06 00:12:29]

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

[commit-bot: I haz the power, 2015-06-06 00:12:30]

Dry run: This issue passed the CQ dry run.

[philipj_slow, 2015-06-06 06:29:20]

philipj@opera.com changed reviewers:
+ jl@opera.com

[philipj_slow, 2015-06-06 06:29:20]

PTAL

[Jens Widell, 2015-06-06 06:36:20]

LGTM

[philipj_slow, 2015-06-06 06:39:36]

The CQ bit was checked by philipj@opera.com

[commit-bot: I haz the power, 2015-06-06 06:39:40]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1164533007/1

[commit-bot: I haz the power, 2015-06-06 06:44:33]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=196624