ICU update to 54 step 3

ICU update to 54 step 3

A. Converter update per HTML encoding spec along with changes in
  the encoding name alias table.
B. Remove all the codes for converters Blink and Chromium do not need
(SCSU, Lotus, ISO-2022-xx other than JP, BOCU, UTF-7, etc).

This is reapplying the following CLs (that we used for ICU 52.1) to ICU 54.1 :

https://codereview.chromium.org/598383002
https://codereview.chromium.org/654153002

We have two upstream bugs filed for A and B above:
  http://www.icu-project.org/trac/ticket/11296
  http://www.icu-project.org/trac/ticket/10303


In addiition to A and B, we unified Big5 and Big5-HKSCS per
the encoding spec (bug 277868). That also includes properly supporting
the four 2-character sequences ( see http://crbug.com/277868#c3 ).
big5_gen.sh deviates from the current spec to work around a bug
in the spec. (see https://www.w3.org/Bugs/Public/show_bug.cgi?id=27878)

Moreover, ucmlocal.mk is added to list only encodings we want to support.

Also, tighten the state table for windows-946-2000.ucm that we use
for EUC-KR for now. And, drop 'base' map for windows-{936,949}-2000.ucm.

Finally, add euc-kr-html.ucm along with scripts/euckr_gen.sh, but
it is not yet used pending the resolution of bug 450312.

Data size checkpoint: 20,566,864 bytes (the original ICU 54=25,343,024)

BUG=277868, 428145, 450312
TEST=net_unittests --gtest_filter="*ilenameUtil*"
TEST=base_unittests --gtest_filter="*Conv*"
TEST=browser_tests --gtest_filter="*ncoding*"
TEST=Blink: fast/encoding/*
R=jsbell@chromium.org, mark@chromium.org

Committed: https://chromium.googlesource.com/chromium/deps/icu/+/afd723ba594ba3e0d00cc10bc8ca8dbae57bb04a

[jungshik at Google, 2015-01-20 19:48:51]

jshin@chromium.org changed reviewers:
+ jsbell@chromium.org, mark@chromium.org

[jungshik at Google, 2015-01-20 19:48:52]

Can you take a look? Thanks

[Mark Mentovai, 2015-01-20 19:57:29]

LGTM

[jsbell, 2015-01-20 21:47:22]

cursory scan lgtm with some script nits

https://codereview.chromium.org/839713003/diff/20001/scripts/big5_gen.sh
File scripts/big5_gen.sh (right):

https://codereview.chromium.org/839713003/diff/20001/scripts/big5_gen.sh#newc...
scripts/big5_gen.sh:2: # Copyright (c) 2014 The Chromium Authors. All rights
reserved.
2015
No (c) per http://www.chromium.org/developers/coding-style#TOC-File-headers

https://codereview.chromium.org/839713003/diff/20001/scripts/big5_gen.sh#newc...
scripts/big5_gen.sh:7: #   http://encoding.spec.whatwg.org/#big5
nit: can use https everywhere

https://codereview.chromium.org/839713003/diff/20001/scripts/big5_gen.sh#newc...
scripts/big5_gen.sh:81: #curl -o index-big5.txt
https://encoding.spec.whatwg.org/index-big5.txt
Commented out...?

(I should note that I get handshake errors with curl on our ubuntu build these
days when trying to fetch files over https, presumably due to recent security
fixes)

https://codereview.chromium.org/839713003/diff/20001/scripts/euckr_gen.sh
File scripts/euckr_gen.sh (right):

https://codereview.chromium.org/839713003/diff/20001/scripts/euckr_gen.sh#new...
scripts/euckr_gen.sh:2: # Copyright (c) 2015 The Chromium Authors. All rights
reserved.
No (c) per http://www.chromium.org/developers/coding-style#TOC-File-headers

[jungshik at Google, 2015-01-21 21:24:11]

Committed patchset #6 (id:50001) manually as
afd723ba594ba3e0d00cc10bc8ca8dbae57bb04a (presubmit successful).