Fix windows build.

R=svenpanne@chromium.org
BUG=

Review URL: https://chromiumcodereview.appspot.com/14476003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14417 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/assembler.h

@@ -50,7 +50,7 @@ class ApiFunction;
 
 namespace internal {
 
-struct StatsCounter;
+class StatsCounter;
 // -----------------------------------------------------------------------------
 // Platform independent assembler base class.