Clean up straggler classes to use embedded signin in page in the new profiles world.

components/signin/core/browser/signin_metrics.cc

Index: components/signin/core/browser/signin_metrics.cc
diff --git a/components/signin/core/browser/signin_metrics.cc b/components/signin/core/browser/signin_metrics.cc
index aa851344572a1cc895ea053ddca06c7cbad4feef..0ec35218bb55438638cfc61ea48d622b96f337c2 100644
--- a/components/signin/core/browser/signin_metrics.cc
+++ b/components/signin/core/browser/signin_metrics.cc
@@ -64,6 +64,10 @@ void LogSigninProfile(bool is_first_run, base::Time install_date) {
                        elapsed_time.InMinutes());
 }
 
+void LogSigninSource(Source source) {
+  UMA_HISTOGRAM_ENUMERATION("Signin.SigninSource", source, HISTOGRAM_MAX);
+}
+
 void LogSigninAddAccount() {
   // Account signin may fail for a wide variety of reasons. There is no
   // explicit false, but one can compare this value with the various UI