ART: Move DexCache arrays to native.

This CL has a companion CL in libcore/
    https://android-review.googlesource.com/162985

Change-Id: Icbc9e20ad1b565e603195b12714762bb446515fa
diff --git a/runtime/mirror/class-inl.h b/runtime/mirror/class-inl.h
index b2c6e4d..10b381d 100644
--- a/runtime/mirror/class-inl.h
+++ b/runtime/mirror/class-inl.h
@@ -817,12 +817,12 @@
   }
 }
 
-inline void Class::SetDexCacheStrings(ObjectArray<String>* new_dex_cache_strings) {
-  SetFieldObject<false>(DexCacheStringsOffset(), new_dex_cache_strings);
+inline void Class::SetDexCacheStrings(GcRoot<String>* new_dex_cache_strings) {
+  SetFieldPtr<false>(DexCacheStringsOffset(), new_dex_cache_strings);
 }
 
-inline ObjectArray<String>* Class::GetDexCacheStrings() {
-  return GetFieldObject<ObjectArray<String>>(DexCacheStringsOffset());
+inline GcRoot<String>* Class::GetDexCacheStrings() {
+  return GetFieldPtr<GcRoot<String>*>(DexCacheStringsOffset());
 }
 
 template<class Visitor>