Add UMA for policy load result of enrolled Chrome OS devices.

chrome/browser/chromeos/policy/device_cloud_policy_store_chromeos.cc

 // Copyright (c) 2012 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.
 
 #include "chrome/browser/chromeos/policy/device_cloud_policy_store_chromeos.h"
 
 #include "base/bind.h"
+#include "base/metrics/sparse_histogram.h"
 #include "base/sequenced_task_runner.h"
 #include "chrome/browser/chromeos/policy/device_policy_decoder_chromeos.h"
 #include "chrome/browser/chromeos/policy/enterprise_install_attributes.h"
 #include "chrome/browser/chromeos/policy/proto/chrome_device_policy.pb.h"
 #include "policy/proto/device_management_backend.pb.h"
 
 namespace em = enterprise_management;
 
 namespace policy {
 
 DeviceCloudPolicyStoreChromeOS::DeviceCloudPolicyStoreChromeOS(
     chromeos::DeviceSettingsService* device_settings_service,
     EnterpriseInstallAttributes* install_attributes,
     scoped_refptr<base::SequencedTaskRunner> background_task_runner)
     : device_settings_service_(device_settings_service),
       install_attributes_(install_attributes),
       background_task_runner_(background_task_runner),
+      uma_done_(false),
       weak_factory_(this) {
   device_settings_service_->AddObserver(this);
 }
 
 DeviceCloudPolicyStoreChromeOS::~DeviceCloudPolicyStoreChromeOS() {
   device_settings_service_->RemoveObserver(this);
 }
 
 void DeviceCloudPolicyStoreChromeOS::Store(
     const em::PolicyFetchResponse& policy) {
@@ skipping 91 matching lines @@
   UpdateFromService();
 }
 
 void DeviceCloudPolicyStoreChromeOS::UpdateFromService() {
   if (!install_attributes_->IsEnterpriseDevice()) {
     status_ = STATUS_BAD_STATE;
     NotifyStoreError();
     return;
   }
 
+  // Fill UMA histogram once per session.  Skip temp validation error because it
+  // is not a definitive result (policy load will be retried).
+  const chromeos::DeviceSettingsService::Status status =
+      device_settings_service_->status();
+  if (!uma_done_ &&
+      status != chromeos::DeviceSettingsService::STORE_TEMP_VALIDATION_ERROR) {
+    uma_done_ = true;
+    UMA_HISTOGRAM_SPARSE_SLOWLY(
+        "Enterprise.EnrolledPolicyHasDMToken",

[Alexei Svitkine (slow), 2014/05/26 17:27:11]

This looks like a boolean histogram, so there's no need for it to be sparse. Use
UMA_HISTOGRAM_BOOLEAN instead.

[Thiemo Nagel, 2014/05/26 17:54:30]

Thanks for catching this!  I had started with a more complex histogram and
simplified it until there were only two bins left...

+        status == chromeos::DeviceSettingsService::STORE_SUCCESS &&
+        device_settings_service_->policy_data() &&
+        !device_settings_service_->policy_data()->has_request_token());

[Alexei Svitkine (slow), 2014/05/26 17:27:11]

Nit: Refactor this into a local bool and use that var in the macro.

[Thiemo Nagel, 2014/05/26 17:54:30]

Done.

+  }
+
   switch (device_settings_service_->status()) {
     case chromeos::DeviceSettingsService::STORE_SUCCESS: {
       status_ = STATUS_OK;
       policy_.reset(new em::PolicyData());
       if (device_settings_service_->policy_data())
         policy_->MergeFrom(*device_settings_service_->policy_data());
 
       PolicyMap new_policy_map;
       if (is_managed()) {
         DecodeDevicePolicy(*device_settings_service_->device_settings(),
@@ skipping 16 matching lines @@
     case chromeos::DeviceSettingsService::STORE_VALIDATION_ERROR:
     case chromeos::DeviceSettingsService::STORE_TEMP_VALIDATION_ERROR:
       status_ = STATUS_LOAD_ERROR;
       break;
   }
 
   NotifyStoreError();
 }
 
 }  // namespace policy