Add inferred register category map to Method object.

Change-Id: I69456c79eb3ce3df1924bffe4db5314b0552f1de
diff --git a/src/compiler_llvm/method_compiler.cc b/src/compiler_llvm/method_compiler.cc
index cf0ea3e..767897c 100644
--- a/src/compiler_llvm/method_compiler.cc
+++ b/src/compiler_llvm/method_compiler.cc
@@ -16,6 +16,7 @@
 
 #include "method_compiler.h"
 
+#include "backend_types.h"
 #include "compiler.h"
 #include "ir_builder.h"
 #include "logging.h"