For consistency, put deleted ctors at the beginning of the class
definition.

If the default copy ctor or assignment operator is not deleted,
and the default implementation is used, leave it commented out to
indicate it is intentional.

Also, fixed one C++11 related TODO.

BUG= none
R=jvoung@chromium.org, kschimpf@google.com

Review URL: https://codereview.chromium.org/656123003