VM [KERNEL] Fix performance issue in KernelReader

runtime/vm/kernel_reader.h

Index: runtime/vm/kernel_reader.h
diff --git a/runtime/vm/kernel_reader.h b/runtime/vm/kernel_reader.h
index 5912c3694d2e9dd3b4e37a2837ee8ebb103644d9..e2c42cb3c685d95890911660ba09e2812c9f1508 100644
--- a/runtime/vm/kernel_reader.h
+++ b/runtime/vm/kernel_reader.h
@@ -76,7 +76,9 @@ class KernelReader {
   void ReadProcedure(const dart::Library& library,
                      const dart::Class& owner,
                      Procedure* procedure,
-                     Class* kernel_klass = NULL);
+                     Class* kernel_klass);
+
+  RawArray* MakeFunctionsArray();
 
   // If klass's script is not the script at the uri index, return a PatchClass
   // for klass whose script corresponds to the uri index.
@@ -109,6 +111,9 @@ class KernelReader {
 
   Mapping<CanonicalName, dart::Library> libraries_;
   Mapping<CanonicalName, dart::Class> classes_;
+
+  GrowableArray<const dart::Function*> functions_;
+  GrowableArray<const dart::Field*> fields_;
 };
 
 }  // namespace kernel