Fix ntp-tiles-internals crash in incognito mode

components/ntp_tiles/webui/ntp_tiles_internals_message_handler.cc

Index: components/ntp_tiles/webui/ntp_tiles_internals_message_handler.cc
diff --git a/components/ntp_tiles/webui/ntp_tiles_internals_message_handler.cc b/components/ntp_tiles/webui/ntp_tiles_internals_message_handler.cc
index 4dce944c2442d3d0334c869d55c90f57fda900dc..9f876ee7efbebbdabcf9f075dff2bff721680217 100644
--- a/components/ntp_tiles/webui/ntp_tiles_internals_message_handler.cc
+++ b/components/ntp_tiles/webui/ntp_tiles_internals_message_handler.cc
@@ -44,6 +44,9 @@ void NTPTilesInternalsMessageHandler::RegisterMessages(
 
 void NTPTilesInternalsMessageHandler::HandleRegisterForEvents(
     const base::ListValue* args) {
+  if (!client_->SupportsNTPTiles()) {
+    return;
+  }
   DCHECK(args->empty());
 
   SendSourceInfo();
@@ -54,6 +57,9 @@ void NTPTilesInternalsMessageHandler::HandleRegisterForEvents(
 
 void NTPTilesInternalsMessageHandler::HandleUpdate(
     const base::ListValue* args) {
+  if (!client_->SupportsNTPTiles()) {
+    return;
+  }
   const base::DictionaryValue* dict = nullptr;
   DCHECK_EQ(1u, args->GetSize());
   args->GetDictionary(0, &dict);