Add an UMA stat to be able to see if the User pods are show on start screen,

and if not, what disabled them: the local setting or domain policy.

BUG=470383

Review URL: https://codereview.chromium.org/1064843003

Cr-Commit-Position: refs/heads/master@{#324206}

chrome/browser/chromeos/login/session/user_session_manager.cc

@@ -10,6 +10,7 @@
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/logging.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/path_service.h"
 #include "base/prefs/pref_member.h"
 #include "base/prefs/pref_registry_simple.h"
@@ -1462,6 +1463,9 @@ void UserSessionManager::OnEasyUnlockKeyOpsFinished(
 
 void UserSessionManager::ActiveUserChanged(
     const user_manager::User* active_user) {
+  if (!user_manager::UserManager::Get()->IsCurrentUserNew())
+    SendUserPodsMetrics();
+
   Profile* profile = ProfileHelper::Get()->GetProfileByUser(active_user);
   // If profile has not yet been initialized, delay initialization of IME.
   if (!profile)
@@ -1586,4 +1590,27 @@ void UserSessionManager::InjectStubUserContext(
   authenticator_ = NULL;
 }
 
+void UserSessionManager::SendUserPodsMetrics() {
+  bool show_users_on_signin;
+  CrosSettings::Get()->GetBoolean(kAccountsPrefShowUserNamesOnSignIn,
+                                  &show_users_on_signin);
+  bool is_enterprise_managed = g_browser_process->platform_part()
+                                   ->browser_policy_connector_chromeos()
+                                   ->IsEnterpriseManaged();
+  UserPodsDisplay display;
+  if (show_users_on_signin) {
+    if (is_enterprise_managed)
+      display = USER_PODS_DISPLAY_ENABLED_MANAGED;
+    else
+      display = USER_PODS_DISPLAY_ENABLED_REGULAR;
+  } else {
+    if (is_enterprise_managed)
+      display = USER_PODS_DISPLAY_DISABLED_MANAGED;
+    else
+      display = USER_PODS_DISPLAY_DISABLED_REGULAR;
+  }
+  UMA_HISTOGRAM_ENUMERATION("UserSessionManager.UserPodsDisplay", display,
+                            NUM_USER_PODS_DISPLAY);
+}
+
 }  // namespace chromeos

chrome/browser/chromeos/login/session/user_session_manager.h

@@ -371,6 +371,23 @@ class UserSessionManager
     should_launch_browser_ = should_launch_browser;
   }
 
+  // The user pods display type for histogram.
+  enum UserPodsDisplay {
+    // User pods enabling or disabling is possible either via local settings or
+    // via domain policy. The former method only applies to regular devices,
+    // whereas the latter is for enterprise-managed devices. Therefore, we have
+    // four possible combiations.
+    USER_PODS_DISPLAY_ENABLED_REGULAR = 0,
+    USER_PODS_DISPLAY_ENABLED_MANAGED = 1,
+    USER_PODS_DISPLAY_DISABLED_REGULAR = 2,
+    USER_PODS_DISPLAY_DISABLED_MANAGED = 3,
+    // Maximum histogram value.
+    NUM_USER_PODS_DISPLAY = 4
+  };
+
+  // Sends metrics for user pods display when existing user has logged in.
+  void SendUserPodsMetrics();
+
   UserSessionManagerDelegate* delegate_;
 
   // Authentication/user context.

tools/metrics/histograms/histograms.xml

@@ -42293,6 +42293,14 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="UserSessionManager.UserPodsDisplay" enum="UserPodsDisplay">
+  <owner>ginkage@chromium.org</owner>
+  <summary>
+    Whether the user pods were enabled during login, and what could disable
+    them.
+  </summary>
+</histogram>
+
 <histogram name="V8.ASTOptimization">
   <obsolete>
     This histogram is no longer present in V8.
@@ -62424,6 +62432,13 @@ To add a new entry, add it with any value and run test to compute valid value.
   <int value="0" label="WiFi Scan"/>
 </enum>
 
+<enum name="UserPodsDisplay" type="int">
+  <int value="0" label="Enabled by local settings"/>
+  <int value="1" label="Enabled by domain policy"/>
+  <int value="2" label="Disabled by local settings"/>
+  <int value="3" label="Disabled by domain policy"/>
+</enum>
+
 <enum name="UserSelectableSyncType" type="int">
   <int value="0" label="Bookmarks"/>
   <int value="1" label="Preferences"/>