Roll ICU to 291774

Roll ICU to 291774

See https://codereview.chromium.org/497543003

fast/encoding/api/ascii-supersets.html has to be rebaselined because
now that Shift_JIS acts as an ASCII superset.
See https://codereview.chromium.org/513413003/

BUG=277062, 404445
TEST=Blink: fast/encoding/* all pass except for
fast/encoding/api/ascii-supersets.html that should fail by *passing*
the test for Shift_JIS, which is expected to fail. Blink layout tests needs
to be updated.
TEST=browser_tests --gtest_filter="*ncoding*"
TEST=In JS console, run the following to check if Europe/Moscow is
3 hrs ahead of UTC after Oct 26 and 4 hrs ahead before that and
if Asia/Kamchatka remains 12 hrs ahead of UTC.
  nov1_2014_1500=new Date("11/01/2014 15:00Z")
  nov1_2014_1500.toLocaleString("en", {timeZone: "Europe/Moscow"})
  nov1_2014_1500.toLocaleString("en", {timeZone: "UTC"})
  nov1_2014_1500.toLocaleString("en", {timeZone: "Asia/Kamchatka"})
  oct24_2014_1500=new Date("10/24/2014 15:00Z")
  oct24_2014_1500.toLocaleString("en", {timeZone: "Europe/Moscow"})
  oct24_2014_1500.toLocaleString("en", {timeZone: "UTC"})
  oct24_2014_1500.toLocaleString("en", {timeZone: "Asia/Kamchatka"})
TEST=net_unittest --gtest_filter="*ilenameUtil*"
TEST=base_unittests --gtest_filter="*Conv*"
TBR=jsbell@chromium.org, nkostylev@chromium.org

Committed: https://crrev.com/08560e0d4c6f016bd1a6bb05020a36cb50c523cc
Cr-Commit-Position: refs/heads/master@{#293034}

[jungshik at Google, 2014-09-02 22:12:15]

I'll TBR this.

[jungshik at Google, 2014-09-02 22:12:18]

The CQ bit was checked by jshin@chromium.org

[commit-bot: I haz the power, 2014-09-02 22:13:09]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/jshin@chromium.org/528083002/1

[commit-bot: I haz the power, 2014-09-02 23:12:58]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  win_chromium_x64_rel_swarming on tryserver.chromium.win
(http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_x64_...)

[commit-bot: I haz the power, 2014-09-03 01:02:21]

Committed patchset #1 (id:1) as f0032027631047d4281ecbfd45669233aae1664f

[commit-bot: I haz the power, 2014-09-10 03:22:21]

Patchset 1 (id:??) landed as
https://crrev.com/08560e0d4c6f016bd1a6bb05020a36cb50c523cc
Cr-Commit-Position: refs/heads/master@{#293034}

[Nikita (slow), 2014-09-11 22:25:08]

lgtm