Turn on C++11 when building with Clang, as in Chromium r170968, r197483, and r220729.
Turn on C++11 when building with Clang, as in Chromium r170968, r197483, and
r220729.

mark-chromium/mini_chromium,Chilledheart/mini_chromium,Chilledheart/mini_chromium,chromium/mini_chromium,chromium/mini_chromium,Chilledheart/mini_chromium,bowlofstew/mini_chromium,chromium/mini_chromium,bowlofstew/mini_chromium,mark-chromium/mini_chromium,mark-chromium/mini_chromium,bowlofstew/mini_chromium