Introduce firstEphemeralRangeOf().

Introduce firstEphemeralRangeOf().

Provide an EphemeralRange counterpart to firstRangeOf() and make use of
it where possible.

R=
BUG=388681
Committed: https://crrev.com/b0d73e182c0a4e9b26d3207ab1c0c2871904bc8e
git-svn-id: svn://svn.chromium.org/blink/trunk@202090 bbb929c8-8fbe-4397-9dbb-9b2b20218538

[sof, 2015-09-10 11:22:42]

sigbjornf@opera.com changed reviewers:
+ haraken@chromium.org, yosin@chromium.org

[sof, 2015-09-10 11:22:43]

please take a look.

Split out from https://codereview.chromium.org/1329253002/ & trying to follow up
the feedback from there. However,

 - kept this as firstEphemeralRangeOf(), i.e., with the "Of" suffix.
 - other uses of firstRangeOf() do not seem straightforward to convert.
 - inlining firstRangeOf() wasn't done. i don't think we should do that.

[haraken, 2015-09-10 11:52:55]

LGTM but let's wait for yosin's approval.

[sof, 2015-09-10 12:40:44]

On 2015/09/10 11:52:55, haraken wrote:
> LGTM but let's wait for yosin's approval.

thanks, certainly.

[yosin_UTC9, 2015-09-11 00:57:03]

lgtm

Thanks so much!
☆⌒(*＾-ﾟ)v

[yosin_UTC9, 2015-09-11 00:57:08]

The CQ bit was checked by yosin@chromium.org

[commit-bot: I haz the power, 2015-09-11 00:57:17]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1332823002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1332823002/20001

[commit-bot: I haz the power, 2015-09-11 02:09:40]

Committed patchset #2 (id:20001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=202090

[commit-bot: I haz the power, 2015-09-23 12:17:50]

Patchset 2 (id:??) landed as
https://crrev.com/b0d73e182c0a4e9b26d3207ab1c0c2871904bc8e