Add base::mac::ScopedMachPort::reset, as in Chromium r193638.
Turn on C++11 when building with Clang, as in Chromium r170968, r197483, and
r220729.
Turn on -Wobjc-missing-property-synthesis, as in Chromium r167783.
Turn on -Wstring-conversion, as in Chromium r183998.
Move string16 from base to base/strings as in Chromium r205050.
Move string_number_conversions from base to base/strings as in Chromium r181161.
Move string_util from base to base/strings as in Chromium r205050.
Move stringprintf from base to base/strings as in Chromium r205050.
Move utf_string_conversions and utf_string_conversion_utils from base to base/strings and add base namespace, as in Chromium r198542 and r181183.
Move sys_string_conversions from base into base/mac as in Chromium r181345.
Move eintr_wrapper.h from base to base/posix as in Chromium r167739.