Revert of Revert of Revert of Revert of Turn on icu_use_data_file_flag on CrOS (https://codereview.chromium.org/163173003/)

Reason for revert:
The original CL (https://src.chromium.org/viewvc/chrome?view=rev&revision=251213 )  was reverted (and reverted twice more) because VMtest on chromeos-{x86,amd64} failed to find icudtl.dat. It turned out that my Chrome OS side change (chromeos-chrome.ebuild) was not picked up by build bots until several hours after landing of that CL. 

It's now picked up [1] and VMtest (on chromeos_x86 bot) finally passed with the original CL still in. 

So, I'm re-landing the original CL by reverting.  


[1] See LGKMSync section at http://build.chromium.org/p/chromium.chromiumos/builders/ChromiumOS%20%28x86%29/builds/19858

Original issue's description:
> Revert of Revert of Revert of Turn on icu_use_data_file_flag on CrOS (https://codereview.chromium.org/164333003/)
> 
> Reason for revert:
> CrOS-side change (chromeos-chrome.ebuild) may not be used by a buildbot.  
> 
> ./1_autotest_tests/results-27-experimental_login_OwnershipNotRetaken/login_OwnershipNotRetaken/sysinfo/var/log/ui/ui.LATEST still has 
> 
> [0214/002103:FATAL:content_main_runner.cc(735)] Check failed: base::i18n::InitializeICU()
> 
> Original issue's description:
> > Revert of Revert of Turn on icu_use_data_file_flag on CrOS (https://codereview.chromium.org/165593002/)
> > 
> > Reason for revert:
> > https://chromium-review.googlesource.com/#/c/185937/ just got landed and this CL can go in now. 
> > 
> > Original issue's description:
> > > Revert of Turn on icu_use_data_file_flag on CrOS (https://codereview.chromium.org/163793004/)
> > > 
> > > Reason for revert:
> > > https://chromium-review.googlesource.com/#/c/185937/ has to go in first. 
> > > 
> > > 
> > > Original issue's description:
> > > > Turn on icu_use_data_file_flag on CrOS
> > > > 
> > > > See also https://chromium-review.googlesource.com/#/c/185937/
> > > > 
> > > > The switch has to be turned on in two places (chromeos-chrome.ebuild and
> > > > build/common.gypi). One or the other can get landed separately, though.
> > > > 
> > > > BUG=72633
> > > > TEST=net_unittests:*IDN* and base_unittests:*String*
> > > > TBR=mark
> > > > 
> > > > Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=251213
> > > 
> > > TBR=mark@chromium.org
> > > NOTREECHECKS=true
> > > NOTRY=true
> > > BUG=72633
> > > 
> > > Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=251214
> > 
> > TBR=mark@chromium.org
> > NOTREECHECKS=true
> > NOTRY=true
> > BUG=72633
> > 
> > Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=251220
> 
> TBR=mark@chromium.org
> NOTREECHECKS=true
> NOTRY=true
> BUG=72633
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=251276

TBR=mark@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=72633

Review URL: https://codereview.chromium.org/166513002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251279 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 251279