Roll src/third_party/icu 8ac906f:d8b2a9d7 (svn 292317:292476)

      Summary of changes available at:
https://chromium.googlesource.com/chromium/deps/icu52/+log/8ac906f..6ea11f3

https://chromium.googlesource.com/chromium/deps/icu52/+log/6ea11f3..d8b2a9d

In addition, change the encoding menu, encoding preferences, and browser tests accordingly;
1. unify iso-8859-1 with windows-1252 in the menu (the name to use is windows-1252)
2. update the encoding preference (default encoding, etc) for various locales.
3. update the test result/expectation.

Re-enable tests disabled in https://codereview.chromium.org/643993004/

TBR=jsbell@chromium.org
BUG=412053
TEST=browser_tests
    BrowserEncodingTest.TestEncodingAutoDetect
    BrowserEncodingTest.TestOverrideEncoding
    EncodingAliases/BrowserEncodingTest.TestEncodingAliasMapping
    SavePageBrowserTest.FileNameFromPageTitle
    SavePageBrowserTest.SaveCompleteHTML
    PrefsTabHelperBrowserTest.WebPrefs
TEST=net_unittest --gtest_filter=&quot*ilenameUtil*&quot
TEST=base_unittests --gtest_filter=&quot*Conv*&quot
TEST=Blink: fast/encoding/*
TEST=http://www.w3.org/International/tests/repository/encoding/indexes/results-indexes
TEST=http://www.w3.org/International/tests/repository/encoding/indexes/results-aliases
TEST=http://www.w3.org/International/tests/repository/run?manifest=encoding/indexes&test=windows-1253_test
TEST=http://www.w3.org/International/tests/repository/run?manifest=encoding/indexes&test=windows-874_test

Review URL: https://codereview.chromium.org/649413002

Cr-Commit-Position: refs/heads/master@{#300643}