Adding instrumentation to locate the source of jankiness.

components/signin/core/browser/about_signin_internals.cc

Index: components/signin/core/browser/about_signin_internals.cc
diff --git a/components/signin/core/browser/about_signin_internals.cc b/components/signin/core/browser/about_signin_internals.cc
index 9f2a864e20806648a8dfb3d21a3c46f39b35ed2d..e88b0f0d7e6610707d5564df528a3ae0d75e2457 100644
--- a/components/signin/core/browser/about_signin_internals.cc
+++ b/components/signin/core/browser/about_signin_internals.cc
@@ -230,6 +230,11 @@ void AboutSigninInternals::NotifyObservers() {
 
   scoped_ptr<base::DictionaryValue> signin_status_value =
       signin_status_.ToValue(client_->GetProductVersion());
+
+  tracked_objects::ScopedTracker tracking_profile1(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "422460 AboutSigninInternals::NotifyObservers1"));
+
   FOR_EACH_OBSERVER(AboutSigninInternals::Observer,
                     signin_observers_,
                     OnSigninStateChanged(signin_status_value.get()));