Make the strict-mode calling convention for contextual calls the default one.

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index 7a2d46c4b4315a96ad86ef7cb8c79458fef66b9b..66c09b060f7de54aa8dfefe214795813abf31137 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -11336,11 +11336,14 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_GetFrameDetails) {
     // by creating correct wrapper object based on the calling frame's
     // native context.
     it.Advance();
-    Handle<Context> calling_frames_native_context(
-        Context::cast(Context::cast(it.frame()->context())->native_context()));
-    ASSERT(!receiver->IsUndefined() && !receiver->IsNull());
-    receiver =
-        isolate->factory()->ToObject(receiver, calling_frames_native_context);
+    if (receiver->IsUndefined() || receiver->IsNull()) {
+      Context* context = function->context();
+      receiver = handle(context->global_object()->global_receiver());
+    } else {
+      Context* context = Context::cast(it.frame()->context());
+      Handle<Context> native_context(Context::cast(context->native_context()));
+      receiver = isolate->factory()->ToObject(receiver, native_context);
+    }
   }
   details->set(kFrameDetailsReceiverIndex, *receiver);