Remove KeyboardEvent.altGraphKey

Remove KeyboardEvent.altGraphKey

Added to WebKit in 2003:
http://trac.webkit.org/changeset/5402

But never standardized:
http://www.w3.org/TR/DOM-Level-3-Events/#interface-KeyboardEvent

It is always false for real events in Chromium. Synthetic events can be
created where it is true using initKeyboardEvent, which is also not per
spec.

Ad-hoc testing with document.createEvent('KeyboardEvent').altGraphKey
shows that this attribute is not supported in IE11, Firefox Nightly or
Opera 12.16, i.e. only WebKit ever added this.

All in all, it seems very unlikely that content could depend on this,
and thus the deprecation process is skipped.

BUG=399451
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=179545

[philipj_slow, 2014-07-31 21:46:39]

PTAL, this one seems trivial enough to avoid spamming blink-dev.

[Rick Byers, 2014-08-01 13:02:03]

LGTM

I agree this is very unlikely to be an issue and am fine skipping the process. 
Eric (as an API owner) should probably weigh in on that before you submit
though.

Rick

[Rick Byers, 2014-08-01 13:03:13]

On 2014/08/01 13:02:03, Rick Byers wrote:
> LGTM
> 
> I agree this is very unlikely to be an issue and am fine skipping the process.

> Eric (as an API owner) should probably weigh in on that before you submit
> though.
> 
> Rick

By the way, this SO article suggests the prevailing wisdom is to ignore this bit
in webkit as strictly misleading:
http://stackoverflow.com/questions/10657346/detect-alt-gr-alt-graph-modifier-...

[philipj_slow, 2014-08-03 14:11:53]

Ping eseidel

[philipj_slow, 2014-08-05 20:59:01]

abarth, can you take a look? It's a bit similar to the
webkitDirectionInvertedFromDevice case.

[abarth-chromium, 2014-08-05 21:01:27]

lgtm

[commit-bot: I haz the power, 2014-08-05 21:05:26]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/philipj@opera.com/434683002/1

[commit-bot: I haz the power, 2014-08-05 23:26:07]

Change committed as 179545