* Update the pre-built ICU data files for all platforms

  source/data/in/icudtl.dat for non-Android platforms
  {linux,mac}/icudt*.S for linux/mac
  android/icudtl.dat and android/icudt*.S for Android
  windows/icudt.dll for Windows

* Update Android data trimming script

  1. Make sure that 'default' calendar is kept in locales where it's relevant
    : root, th, fa, ar_SA, etc.
  2. Add a minimal region data to work around a bug in ICU with pool.res
     handling

* Update gn and gyp files
* And add a TODO comment to update.sh to automate the build file update.
* Add it_CH to the locale list.
* Add sr_Latn to unit/reslocal.mk (required by sh) and
  line_normal_fi to brkitr/brklocal.mk (referred to in brkitr/fi.txt) in
  place of line_fi.

* Update and add scripts for data building
* Completely rewrite README.chromium
* Check-in the prebuilt ICU data files/assembly sources for
  Linux,Mac,Windows,Chrome OS and Android.

BUG=575007
TEST=Blink layout tests, webkit unittests
TEST=All bots can build successfully
TEST=net_unittests --gtest_filter="*ilenameUtil*"
TEST=net_unittests --gtest_filter="*IDN*" (pending bug 336973)
TEST=base_unittests --gtest_filter="*Conv*"
TEST=browser_tests --gtest_filter="*ncoding*"
TEST=base_unittests --gtest_filter="*essage*"
TEST=ui_base_unittests --gtest_filter="*ormat*"
TEST=ui_base_unittests --gtest_filter="L10n*"
R=mark@chromium.org

Review URL: https://codereview.chromium.org/1639543006 .

1. Update the IANA tz db to 2015b.
  - http://mm.icann.org/pipermail/tz-announce/2015-March/000029.html
  - Mongolia decided to observe DST again in 2015 starting on the last
    Sunday in March.
  - Palestine's DST start date is corrected to be March 28 instead of 27th.

2. Add a script to download the tz database files (update_tz.sh)

3. Check in scripts/make_n_copy_data.sh that I've been using to build ICU
   data/assembly files and update README.chromium.

4. Update android/patch_locale.sh to apply android/brkitr.patch as well.

BUG=473288
TEST=1. In JavaScript console, run the following.
  mar27_2015_1200 = new Date("03/27/2015 12:00Z")
  mar28_2015_1200 = new Date("03/28/2015 12:00Z")
  mar27_2015_1200.toLocaleString("en", {timeZone: "Asia/Gaza"}
  mar28_2015_1200.toLocaleString("en", {timeZone: "Asia/Gaza"}
  apr15_2014_1200 = new Date("04/15/2014 12:00Z")
  apr15_2015_1200 = new Date("04/15/2015 12:00Z")
  apr15_2014_1200.toLocaleString("en", {timeZone: "Asia/Ulan_Bator"}
  apr15_2015_1200.toLocaleString("en", {timeZone: "Asia/Ulan_Bator"}

In Asia/Gaza, Mar 27 12:00Z should be 2PM and mar28 12:00Z should be 3PM.
In Asia/Ulan_Bator, April 15 12:00Z should be 8PM in 2014 and should be 9PM
in 2015. Ulan_Bator does not work due to http://crbug.com/364374.

R=mark@chromium.org

Review URL: https://codereview.chromium.org/1051193002