Use Kernel frontend from run_vm_tests.

runtime/vm/kernel_isolate.h

Index: runtime/vm/kernel_isolate.h
diff --git a/runtime/vm/kernel_isolate.h b/runtime/vm/kernel_isolate.h
index 2cbb5f90a19f7f883f53e140fb3501caa18c5abc..7cb9f782b6c205373a82bf17a6248c15e9e3d49c 100644
--- a/runtime/vm/kernel_isolate.h
+++ b/runtime/vm/kernel_isolate.h
@@ -27,7 +27,10 @@ class KernelIsolate : public AllStatic {
   static Dart_Port WaitForKernelPort();
   static Dart_Port KernelPort() { return kernel_port_; }
 
-  static Dart_KernelCompilationResult CompileToKernel(const char* script_uri);
+  static Dart_KernelCompilationResult CompileToKernel(
+      const char* script_uri,
+      int source_files_count = 0,
+      Dart_SourceFile source_files[] = NULL);
 
  protected:
   static Monitor* monitor_;