Add Isolate parameter to Persistent class.

samples/shell.cc

Index: samples/shell.cc
diff --git a/samples/shell.cc b/samples/shell.cc
index 62f404554b2a4b241ae25a76a561be6177a0b3fb..e9057f9e90ab523ba33929fabf755eae6222ba75 100644
--- a/samples/shell.cc
+++ b/samples/shell.cc
@@ -79,7 +79,7 @@ int main(int argc, char* argv[]) {
     result = RunMain(argc, argv);
     if (run_shell) RunShell(context);
     context->Exit();
-    context.Dispose();
+    context.Dispose(context->GetIsolate());
   }
   v8::V8::Dispose();
   return result;