Initialize ClassLinker from image

Change-Id: Ibaf47b4181f7c6603a8b37e2eba8fa6509c927ed
diff --git a/src/object.cc b/src/object.cc
index bfa200a..3200e4d 100644
--- a/src/object.cc
+++ b/src/object.cc
@@ -526,9 +526,15 @@
 // TODO: get global references for these
 Class* String::java_lang_String_ = NULL;
 
-void String::InitClass(Class* java_lang_String) {
+void String::SetClass(Class* java_lang_String) {
+  CHECK(java_lang_String_ == NULL);
+  CHECK(java_lang_String != NULL);
   java_lang_String_ = java_lang_String;
 }
+void String::ResetClass() {
+  CHECK(java_lang_String_ != NULL);
+  java_lang_String_ = NULL;
+}
 
 static const char* kClassStatusNames[] = {
   "Error",