[Metrics] Make MetricsStateManager take a callback param to check if UMA is enabled.

chrome/browser/metrics/metrics_services_manager.cc

 // 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.
 
 #include "chrome/browser/metrics/metrics_services_manager.h"
 
+#include "base/command_line.h"
 #include "chrome/browser/metrics/metrics_service.h"
 #include "chrome/browser/metrics/metrics_state_manager.h"
 #include "chrome/browser/metrics/variations/variations_service.h"
+#include "chrome/common/chrome_switches.h"
+#include "chrome/common/pref_names.h"
 #include "components/rappor/rappor_service.h"
 
+#if defined(OS_CHROMEOS)
+#include "chrome/browser/chromeos/settings/cros_settings.h"
+#endif
+
 MetricsServicesManager::MetricsServicesManager(PrefService* local_state)
     : local_state_(local_state) {
   DCHECK(local_state);
 }
 
 MetricsServicesManager::~MetricsServicesManager() {
 }
 
 MetricsService* MetricsServicesManager::GetMetricsService() {
   DCHECK(thread_checker_.CalledOnValidThread());
@@ skipping 15 matching lines @@
   if (!variations_service_) {
     variations_service_ =
         chrome_variations::VariationsService::Create(local_state_,
                                                      GetMetricsStateManager());
   }
   return variations_service_.get();
 }
 
 metrics::MetricsStateManager* MetricsServicesManager::GetMetricsStateManager() {
   DCHECK(thread_checker_.CalledOnValidThread());
-  if (!metrics_state_manager_)
-    metrics_state_manager_ = metrics::MetricsStateManager::Create(local_state_);
+  if (!metrics_state_manager_) {
+    metrics_state_manager_ = metrics::MetricsStateManager::Create(
+        local_state_,
+        base::Bind(&MetricsServicesManager::IsMetricsReportingEnabled,
+                   base::Unretained(this)));
+  }
   return metrics_state_manager_.get();
 }
+
+// TODO(asvitkine): This function does not report the correct value on Android,
+// see http://crbug.com/362192.
+bool MetricsServicesManager::IsMetricsReportingEnabled() const {
+  // If the user permits metrics reporting with the checkbox in the
+  // prefs, we turn on recording.  We disable metrics completely for
+  // non-official builds, or when field trials are forced.
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kForceFieldTrials))
+    return false;
+
+  bool enabled = false;
+#if defined(GOOGLE_CHROME_BUILD)
+#if defined(OS_CHROMEOS)
+  chromeos::CrosSettings::Get()->GetBoolean(chromeos::kStatsReportingPref,
+                                            &enabled);
+#else
+  enabled = local_state_->GetBoolean(prefs::kMetricsReportingEnabled);
+#endif  // #if defined(OS_CHROMEOS)
+#endif  // defined(GOOGLE_CHROME_BUILD)
+  return enabled;
+}