Add a few more confusable map entries

1. Map Malaylam U+0D1F to 's'.
2. Map 'small-cap-like' Cyrillic letters to "look-alike" Latin lowercase
letters.

The characters in new confusable map entries are replaced by their Latin
"look-alike" characters before the skeleton is calculated to compare with
top domain names.

Bug: 784761,773930
Test: components_unittests --gtest_filter=*IDNToUni*
Change-Id: Ib26664e21ac5eb290e4a2993b01cbf0edaade0ee
Reviewed-on: https://chromium-review.googlesource.com/805214
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Commit-Queue: Jungshik Shin <jshin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521648}
bool IDNSpoofChecker::SimilarToTopDomains(base::StringPiece16 hostname) {
  size_t hostname_length = hostname.length() - (hostname.back() == '.' ? 1 : 0);
  icu::UnicodeString ustr_host(FALSE, hostname.data(), hostname_length);
   if (lgc_letters_n_ascii_.span(ustr_host, 0, USET_SPAN_CONTAINED) ==
       ustr_host.length())
    diacritic_remover_.get()->transliterate(ustr_host);
  extra_confusable_mapper_.get()->transliterate(ustr_host);
 
   UErrorCode status = U_ZERO_ERROR;
   icu::UnicodeString ustr_skeleton;
  uspoof_getSkeletonUnicodeString(checker_, 0, ustr_host, ustr_skeleton,
                                  &status);
   if (U_FAILURE(status))
     return false;
   std::string skeleton;
  return LookupMatchInTopDomains(ustr_skeleton.toUTF8String(skeleton));
 }

bool IDNSpoofChecker::SimilarToTopDomains(base::StringPiece16 hostname) {
  size_t hostname_length = hostname.length() - (hostname.back() == '.' ? 1 : 0);
  icu::UnicodeString ustr_host(FALSE, hostname.data(), hostname_length);
   if (lgc_letters_n_ascii_.span(ustr_host, 0, USET_SPAN_CONTAINED) ==
       ustr_host.length())
    transliterator_.get()->transliterate(ustr_host);
 
   UErrorCode status = U_ZERO_ERROR;
   icu::UnicodeString ustr_skeleton;
  uspoof_getSkeletonUnicodeString(checker_, 0, ustr_host, ustr_skeleton,
                                  &status);
   if (U_FAILURE(status))
     return false;
   std::string skeleton;
  ustr_skeleton.toUTF8String(skeleton);
  return LookupMatchInTopDomains(skeleton);
 }
