Remove unused header in safe_math_impl.h

R=ajwong
TBR=ajwong

Review URL: https://codereview.chromium.org/346743003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@278398 0039d316-1c4b-4281-b951-d872f2087c98

base/numerics/safe_math_impl.h

@@ -11,7 +11,6 @@
 #include <cstdlib>
 #include <limits>
 
-#include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/numerics/safe_conversions.h"
 #include "base/template_util.h"