Fix Native Messaging to handle missing caller RenderWidgetHost.

chrome/browser/extensions/api/messaging/message_service.cc

Index: chrome/browser/extensions/api/messaging/message_service.cc
diff --git a/chrome/browser/extensions/api/messaging/message_service.cc b/chrome/browser/extensions/api/messaging/message_service.cc
index d52997437acc70f5e2c69d466309f7ee3d59bd95..74142f4f723084a88c2c9a6c845dc4638e7efcf4 100644
--- a/chrome/browser/extensions/api/messaging/message_service.cc
+++ b/chrome/browser/extensions/api/messaging/message_service.cc
@@ -403,9 +403,11 @@ void MessageService::OpenChannelToNativeApp(
                                                  source_extension_id));
 
   // Get handle of the native view and pass it to the native messaging host.
+  content::RenderWidgetHost* render_widget_host =
+      content::RenderWidgetHost::FromID(source_process_id, source_routing_id);
   gfx::NativeView native_view =
-      content::RenderWidgetHost::FromID(source_process_id, source_routing_id)->
-          GetView()->GetNativeView();
+      render_widget_host ? render_widget_host->GetView()->GetNativeView()
+                         : NULL;

[not at google - send to devlin, 2014/12/11 17:24:42]

Are we supposed to use nullptr these days? I'm losing track.

Anyway, I may be missing something here, but I traced through the call stack and
I can't see the native view actually used anywhere.

Under the assumption I *am* missing something, then this change lgtm, though it
seems weird passing a potentially NULL native view. You could document in
NativeMessageHost::Create that the view can be null. Or even better... delete it
entirely :)

[Sergey Ulanov, 2014/12/11 19:25:29]

Yes, it should be nullptr. This is my first change in more than 2 month
(parental leave), so I forgot about it. Thanks for catching it.
It's used only on windows to pass chrome window handle to the native process,
e.g. so that it can set correct parent for UAC prompts. See
https://code.google.com/p/chromium/codesearch#chromium/src/chrome/browser/ext...
Added a comment in native_process_launcer.h

[not at google - send to devlin, 2014/12/11 20:19:46]

Where is native_view used then?

 
   std::string error = kReceivingEndDoesntExistError;
   scoped_ptr<NativeMessageHost> native_host = NativeMessageHost::Create(