Track when and how a profile is signed out via UMA.

components/signin/core/browser/signin_metrics.h

Index: components/signin/core/browser/signin_metrics.h
diff --git a/components/signin/core/browser/signin_metrics.h b/components/signin/core/browser/signin_metrics.h
index 0dfa97a06ddb9c2ff6c83e2fa2b18d268269bfb0..1730254aeb120db7ab07a5a00b5749fd9c43e22a 100644
--- a/components/signin/core/browser/signin_metrics.h
+++ b/components/signin/core/browser/signin_metrics.h
@@ -7,6 +7,29 @@
 
 namespace signin_metrics {
 
+// Track all the ways a profile can become signed out as a histogram.
+enum ProfileSignout {

[Evan Stade, 2014/06/19 01:55:13]

what about deleting a profile that's signed in? does that count as sign out?

[Roger Tawa OOO till Jul 10th, 2014/06/19 14:55:13]

It might be possible to track that, but not sure its worth it.  There are other
much more likely ways for a profile to "disappear", like uninstalling chrome, 
user manually deleting the folder, or a profile just never being used again.

[Mike Lerman, 2014/06/19 17:55:48]

I'm creating another CL to track profile deletions, including differentiating
between when the profile was signed in or not
(https://codereview.chromium.org/345733006/). Along with Roger, I don't think
it's an important category to track for SignOut, but if we do decide it would be
valuable it will be tracked in another histogram.

+  // The preference or policy controlling if signin is valid has changed.
+  SIGNOUT_PREF_CHANGED,
+  // The valid pattern for signing in to the Google service changed.
+  GOOGLE_SERVICE_NAME_PATTERN_CHANGED,
+  // The preference or policy controlling if signin is valid changed during
+  // the signin process.
+  SIGNIN_PREF_CHANGED_DURING_SIGNIN,
+  // User clicked to signout.

[Evan Stade, 2014/06/19 01:55:13]

clicked which control? might want to specify

[Mike Lerman, 2014/06/19 17:55:48]

Done.

+  USER_CLICKED_SIGNOUT,
+  // The signin process was aborted, but signin had succeeded, so signout. This
+  // may be due to a server response, policy definition or user action.
+  ABORT_SIGNIN,
+  // The sync server caused the profile to be signed out.
+  SERVER_FORCED_DISABLE,
+  // The credentials are being transfered to a new profile, so the old one is
+  // signed out.
+  TRANSFER_CREDENTIALS,

[Evan Stade, 2014/06/19 01:55:13]

nit: insert newline

[Mike Lerman, 2014/06/19 17:55:48]

Done... but why? Just to separate out the last counting metric?

[Evan Stade, 2014/06/19 21:33:36]

yes

+  // Keep this as the last enum.
+  NUM_PROFILE_SIGNOUT_METRICS,
+};
+
 // Log to UMA histograms and UserCounts stats about a single execution of the
 // AccountReconciler.
 // |total_number_accounts| - How many accounts are in the browser for this
@@ -28,6 +51,9 @@ void LogSigninAccountReconciliation(int total_number_accounts,
 // Track a successful signin.
 void LogSigninAddAccount();
 
+// Track a profile signout.
+void LogSignout(ProfileSignout metric);
+
 }  // namespace signin_metrics
 
 #endif  // COMPONENTS_SIGNIN_CORE_BROWSER_SIGNIN_METRICS_H_