Expose render_process_id to CastShellActivity.

chromecast/browser/cast_content_browser_client.cc

Index: chromecast/browser/cast_content_browser_client.cc
diff --git a/chromecast/browser/cast_content_browser_client.cc b/chromecast/browser/cast_content_browser_client.cc
index f3f2c7df6d88760ab6abcf412a161c13eb40c229..ce8af676505606a1a8070e4580c6bfd3683b1fa8 100644
--- a/chromecast/browser/cast_content_browser_client.cc
+++ b/chromecast/browser/cast_content_browser_client.cc
@@ -194,7 +194,9 @@ CastContentBrowserClient::SelectClientCertificateOnIOThread(
     return CastNetworkDelegate::DeviceCert();
   } else {
     LOG(ERROR) << "Invalid host for client certificate request: "
-               << requesting_url.host();
+               << requesting_url.host()
+               << " with render_process_id: "
+               << render_process_id;
     return NULL;
   }
 }