Use the icu data file on Linux (but not on CrOS)

Set icu_use_data_file_flag to 1 for POSIX (other than Mac/iOS/Android).

Mac and Android will be handled in a separate CL.

This has to wait until https://codereview.chromium.org/111723007/ is rolled in.
(done by https://codereview.chromium.org/118313004/ )

BUG=72633
TEST=All linux builds go through and all tests pass and there's no perf (start-up etc) regression.

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=246678

R=mark@chromium.org, mmoss@chromium.org

Review URL: https://codereview.chromium.org/102413007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247045 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 247045