Fix SetInferredRegCategoryMap. Null check issue.

Change-Id: I5f223517dc930578244d6266be8a932274c43bc0
diff --git a/src/object.cc b/src/object.cc
index 97634d5..27b85b0 100644
--- a/src/object.cc
+++ b/src/object.cc
@@ -393,7 +393,8 @@
 }
 
 void Method::SetInferredRegCategoryMap(const InferredRegCategoryMap* map) {
-  const InferredRegCategoryMap* existing_map = GetInferredRegCategoryMap();
+  const InferredRegCategoryMap* existing_map = GetFieldPtr<const InferredRegCategoryMap*>(
+      OFFSET_OF_OBJECT_MEMBER(Method, gc_map_), false);
 
   DCHECK(existing_map == NULL) << PrettyMethod(this);
   DCHECK(map != NULL) << PrettyMethod(this);
@@ -406,7 +407,7 @@
 void Method::ResetInferredRegCategoryMap() {
   delete GetInferredRegCategoryMap();
   SetFieldPtr<const InferredRegCategoryMap*>(
-    OFFSET_OF_OBJECT_MEMBER(Method, gc_map_), NULL, false);
+      OFFSET_OF_OBJECT_MEMBER(Method, gc_map_), NULL, false);
 }
 
 #endif