Exclude duplicate gmock_mutant functor templates in WIN64
On WIN64, there is only one calling convention. Therefore,
implicit calling conventions and __stdcall are the same, hence
template redefinition errors occur in the previous gmock_mutant.h
on WIN64.
BUG=173697, 166496
TEST=media_unittests target builds without template redefinition errors. With other build errors fixed in privates (ignore C4267 & lift MEDIA...INTRINSICS... definition into yuv_convert.h and use it to not link in methods that use MMX intrinsics), media_unittests executes
Review URL: https://chromiumcodereview.appspot.com/
12208028
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@181348 0039d316-1c4b-4281-b951-d872f2087c98