Improve error message for failing code insertion on about:-URLs

extensions/renderer/programmatic_script_injector.h

Index: extensions/renderer/programmatic_script_injector.h
diff --git a/extensions/renderer/programmatic_script_injector.h b/extensions/renderer/programmatic_script_injector.h
index e6655cdc0a714d524979fb45a4ab94590c183aff..085c92c337e642e0091d82beabed3b9459a52ec3 100644
--- a/extensions/renderer/programmatic_script_injector.h
+++ b/extensions/renderer/programmatic_script_injector.h
@@ -65,6 +65,11 @@ class ProgrammaticScriptInjector : public ScriptInjector {
   // The url of the frame into which we are injecting.
   GURL url_;
 
+  // The URL of the frame's origin. This is usually identical to |url_|, but
+  // could be different for e.g. about:blank URLs. Do not use this value to make
+  // security decisions, to avoid race conditions (e.g. due to navigation).
+  GURL effective_url_;
+
   // The RenderView to which we send the response upon completion.
   content::RenderView* render_view_;