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

components/signin/core/browser/signin_metrics.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_SIGNIN_CORE_BROWSER_SIGNIN_METRICS_H_
 #define COMPONENTS_SIGNIN_CORE_BROWSER_SIGNIN_METRICS_H_
 
 namespace signin_metrics {
 
+// Track all the ways a profile can become signed out as a histogram.
+enum ProfileSignout {
+  // 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.
+  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,
+  // User clicked to signout on android.
+  ANDROID_SIGNOUT,
+  // 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,
+  // 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
 //                           profile.
 // |count_added_to_cookie_jar| - How many accounts were in the browser but not
 //                               the cookie jar.
 // |count_added_to_token| - How may accounts were in the cookie jar but not in
 //                          the browser.
 // |primary_accounts_same| - False if the primary account for the cookie jar
 //                           and the token service were different; else true.
 // |is_first_reconcile| - True if these stats are from the first execution of
 //                        the AccountReconcilor.
 void LogSigninAccountReconciliation(int total_number_accounts,
                                     int count_added_to_cookie_jar,
                                     int count_added_to_token,
                                     bool primary_accounts_same,
                                     bool is_first_reconcile);
 
 // 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_