ContentEditable plaintext-only crash fix.

ContentEditable plaintext-only crash fix.

Calling createLink execCommand on a selection that includes both normal
contentEditable and plaintext-only contentEditable caused a crash when
applying style in ApplyStyleCommand::applyInlineStyleToNodeRange because the
EditingStyle::m_mutableStyle is null.

I do not have a well enough understanding of what is going on here to be sure
this is the correct fix, but trying to move the check for style()->style
further up caused various LayoutTests to fail.

BUG=270031
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=158248

[Z_DONOTUSE, 2013-09-23 23:57:54]

lgtm

Seems reasonable.

[commit-bot: I haz the power, 2013-09-23 23:58:13]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/rune@opera.com/23600068/1

[commit-bot: I haz the power, 2013-09-24 00:13:16]

Retried try job too often on blink_presubmit for step(s) presubmit
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=blink_pres...

[rune, 2013-09-24 03:17:03]

On 2013/09/24 00:13:16, I haz the power (commit-bot) wrote:
> Retried try job too often on blink_presubmit for step(s) presubmit
>
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=blink_pres...

@ojan: your stamp did not work. Because you used ojan1, perhaps?

[leviw_travelin_and_unemployed, 2013-09-24 03:43:41]

Okay. LGTM.

[commit-bot: I haz the power, 2013-09-24 03:44:01]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/rune@opera.com/23600068/1

[commit-bot: I haz the power, 2013-09-24 07:06:08]

Change committed as 158248