Fix bug 20078:

runtime/vm/class_finalizer.cc

Index: runtime/vm/class_finalizer.cc
===================================================================
--- runtime/vm/class_finalizer.cc	(revision 38321)
+++ runtime/vm/class_finalizer.cc	(working copy)
@@ -97,7 +97,6 @@
 // a) when bootstrap process completes (VerifyBootstrapClasses).
 // b) after the user classes are loaded (dart_api).
 bool ClassFinalizer::ProcessPendingClasses() {
-  bool retval = true;
   Isolate* isolate = Isolate::Current();
   ASSERT(isolate != NULL);
   HANDLESCOPE(isolate);
@@ -137,10 +136,13 @@
     class_array = GrowableObjectArray::New();
     object_store->set_pending_classes(class_array);
     VerifyImplicitFieldOffsets();  // Verification after an error may fail.
+
+    return true;
   } else {
-    retval = false;
+    return false;
   }
-  return retval;
+  UNREACHABLE();
+  return true;
 }