[blink] Add a DocumentMarker::MisspellingMarkers helper

[blink] Add a DocumentMarker::MisspellingMarkers helper

This patch adds DocumentMarker::MisspellingMarkers helper to be used instead of
(DocumentMarker::Spelling | DocumentMarker::Grammar) through-out Blink. This
patch is first of two for issue 295190, which aims to add an invisible
DocumentMarker::InCustomSpellcheckDictionary marker to Blink.

BUG=295190
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=158125

[please use gerrit instead, 2013-09-20 00:20:17]

Tony: PTAL.

This patch is the first of two for
https://groups.google.com/a/chromium.org/d/msg/blink-dev/l8liklvqMp8/y2yZXhka....

[tony, 2013-09-20 01:24:59]

LGTM.  It's a bit weird that we use subclasses for AllMarkers and
MisspellingMarkers. I probably would have just made a function that returns the
right type of MarkerTypes, I think that avoids a vtable.  But it's probably not
that big of a deal.

[commit-bot: I haz the power, 2013-09-20 17:07:56]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/rouslan@chromium.org/24198006/5001

[commit-bot: I haz the power, 2013-09-20 17:15:43]

Change committed as 158125

[please use gerrit instead, 2013-09-20 17:19:15]

On 2013/09/20 17:15:43, I haz the power (commit-bot) wrote:
> Change committed as 158125

That was quick. Is it expected that there're no build-bots for blink?

[tony, 2013-09-20 17:24:26]

On 2013/09/20 17:19:15, Rouslan Solomakhin wrote:
> On 2013/09/20 17:15:43, I haz the power (commit-bot) wrote:
> > Change committed as 158125
> 
> That was quick. Is it expected that there're no build-bots for blink?

I think it uses try bot status, but I'm not exactly sure when it decides it
needs to re-run some bots because of failures.  I think nbarth or maruel would
know the exact heuristics.