Revert "Revert "Add basic implementation of IsModifiableClass""

This reverts commit c66c077d40db58ec239f93a9c42b9939439c85c7.

Reason for revert: Problem with preceding CL fixed.

Test: mma -j40 test-art-host
diff --git a/runtime/openjdkjvmti/ti_redefine.h b/runtime/openjdkjvmti/ti_redefine.h
index d6bccb4..01b5eca 100644
--- a/runtime/openjdkjvmti/ti_redefine.h
+++ b/runtime/openjdkjvmti/ti_redefine.h
@@ -80,6 +80,8 @@
                                   unsigned char* dex_data,
                                   std::string* error_msg);
 
+  static jvmtiError IsModifiableClass(jvmtiEnv* env, jclass klass, jboolean* is_redefinable);
+
  private:
   jvmtiError result_;
   art::Runtime* runtime_;
@@ -106,6 +108,10 @@
         error_msg_(error_msg),
         class_sig_(class_sig) { }
 
+  static jvmtiError GetClassRedefinitionError(art::Handle<art::mirror::Class> klass,
+                                              /*out*/std::string* error_msg)
+      REQUIRES_SHARED(art::Locks::mutator_lock_);
+
   static std::unique_ptr<art::MemMap> MoveDataToMemMap(const std::string& original_location,
                                                        jint data_len,
                                                        unsigned char* dex_data,