compile time.
The condition of static_assert() is evaluated at compile time which is safer and
more efficient.
Note that static_assert() requires C++11.
The changes were generated by the misc-static-assert ClangTidy check by alexfh@google.comR=tommi@webrtc.org
Review URL: https://webrtc-codereview.appspot.com/51019004
Cr-Commit-Position: refs/heads/master@{#9231}