Enable icu_use_data_file_flag on Android

0. Roll icu to r249466 to copy Android-specific icudtl.dat
1. Turn it in build/common.gypi by default except for android webview build. Move it inside L2 var dict and pull it up to the top level var dict to make 'Google Chrome' build on Android happy. 
2. Add an entry for icudtl.dat to chrome/chrome_android_paks.gypi so that
it's copied to assets directory for Chrome and related targets. 
3. Extract icudtl.dat from the asset and copy to DIR_ANDROID_APP_DATA and make it world-readable so that child processes (sandboxed with uid) can read it. 
4. Add icudtl.dat to MANDATORY_PAKS list in various Android build targets 

Google Chrome has #4 but in a separate CL ( https://chrome-internal-review.googlesource.com/#/c/155554/ ). That CL will land before this CL. 

This also depends on a Blink change https://codereview.chromium.org/183013006/ 

TBR=avi@chromium.org
BUG=72633
TEST=base_unittests:*Convers*, net_unittests:*IDN*, browser tests on all platforms.
TEST=On Android, 1. Layout tests 
2. build/android/test_runner.py gtest -s webkit_unit_tests 
--gtest_filter=WebFrameTest.SelectRange*

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=253938

Review URL: https://codereview.chromium.org/156333002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255762 0039d316-1c4b-4281-b951-d872f2087c98
Update .DEPS.git

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255763 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 255763