UMA track signed in duration at signout

components/signin/core/browser/signin_manager_base.cc

Index: components/signin/core/browser/signin_manager_base.cc
diff --git a/components/signin/core/browser/signin_manager_base.cc b/components/signin/core/browser/signin_manager_base.cc
index 52172e8f81bba051a7f8880b08974623035116a9..39583f601ac357414e03ad0d978b1f20e33a9c9b 100644
--- a/components/signin/core/browser/signin_manager_base.cc
+++ b/components/signin/core/browser/signin_manager_base.cc
@@ -90,6 +90,8 @@ void SigninManagerBase::SetAuthenticatedUsername(const std::string& username) {
   // user is signed in the two preferences should match. Doing it here as
   // opposed to on signin allows us to catch the upgrade scenario.
   client_->GetPrefs()->SetString(prefs::kGoogleServicesLastUsername, username);
+  client_->GetPrefs()->SetInt64(prefs::kSignedInTime,
+                                base::Time::Now().ToInternalValue());

[Roger Tawa OOO till Jul 10th, 2014/08/12 14:14:52]

Seems like it would be better to put this in OnSignedIn(), right before the call
to SetAuthenticatedUsername().

[Mike Lerman, 2014/08/12 18:07:10]

Done.

 }
 
 void SigninManagerBase::clear_authenticated_username() {