Fix TabSocket.onmessage whoch should be able to retrieve all messages

headless/lib/renderer/headless_content_renderer_client.cc

Index: headless/lib/renderer/headless_content_renderer_client.cc
diff --git a/headless/lib/renderer/headless_content_renderer_client.cc b/headless/lib/renderer/headless_content_renderer_client.cc
index a82418083d448dedfc8f85a0a448b4aa7bd239ca..dff21797bda05ffa3f204e4105d0f16b5a38b22a 100644
--- a/headless/lib/renderer/headless_content_renderer_client.cc
+++ b/headless/lib/renderer/headless_content_renderer_client.cc
@@ -116,6 +116,10 @@ class HeadlessTabSocketBindings
     render_frame()->GetWebFrame()->RequestExecuteV8Function(
         context, GetOnMessageCallback(), context->Global(), arraysize(argv),
         argv, this);
+
+    EnsureTabSocketPtr()->AwaitNextMessageFromEmbedder(
+        base::Bind(&HeadlessTabSocketBindings::OnNextMessageFromEmbedder,
+                   weak_ptr_factory_.GetWeakPtr()));
   }
 
   void InitializeTabSocketBindings(v8::Local<v8::Context> context) {