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

chrome/browser/metrics/metrics_state_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_state_manager.h"
 
 #include "base/command_line.h"
 #include "base/guid.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/sparse_histogram.h"
 #include "base/prefs/pref_registry_simple.h"
 #include "base/prefs/pref_service.h"
 #include "base/rand_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/time/time.h"
 #include "chrome/browser/metrics/cloned_install_detector.h"
 #include "chrome/browser/metrics/machine_id_provider.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
 #include "components/variations/caching_permuted_entropy_provider.h"
 
-#if defined(OS_CHROMEOS)
-#include "chrome/browser/chromeos/settings/cros_settings.h"
-#endif
-
 namespace metrics {
 
 namespace {
 
 // The argument used to generate a non-identifying entropy source. We want no
 // more than 13 bits of entropy, so use this max to return a number in the range
 // [0, 7999] as the entropy source (12.97 bits of entropy).
 const int kMaxLowEntropySize = 8000;
 
 // Default prefs value for prefs::kMetricsLowEntropySource to indicate that the
 // value has not yet been set.
 const int kLowEntropySourceNotSet = -1;
 
 // Generates a new non-identifying entropy source used to seed persistent
 // activities.
 int GenerateLowEntropySource() {
   return base::RandInt(0, kMaxLowEntropySize - 1);
 }
 
 }  // namespace
 
 // static
 bool MetricsStateManager::instance_exists_ = false;
 
-MetricsStateManager::MetricsStateManager(PrefService* local_state)
+MetricsStateManager::MetricsStateManager(
+    PrefService* local_state,
+    const base::Callback<bool(void)>& is_reporting_enabled_callback)
     : local_state_(local_state),
+      is_reporting_enabled_callback_(is_reporting_enabled_callback),
       low_entropy_source_(kLowEntropySourceNotSet),
       entropy_source_returned_(ENTROPY_SOURCE_NONE) {
   ResetMetricsIDsIfNecessary();
   if (IsMetricsReportingEnabled())
     ForceClientIdCreation();
 
   DCHECK(!instance_exists_);
   instance_exists_ = true;
 }
 
 MetricsStateManager::~MetricsStateManager() {
   DCHECK(instance_exists_);
   instance_exists_ = false;
 }
 
 bool MetricsStateManager::IsMetricsReportingEnabled() {
-  // If the user permits metrics reporting with the checkbox in the
-  // prefs, we turn on recording.  We disable metrics completely for
-  // non-official builds.  This can be forced with a flag.
-  const CommandLine* command_line = CommandLine::ForCurrentProcess();
-  if (command_line->HasSwitch(switches::kEnableMetricsReportingForTesting))
-    return true;
-
-  // Disable metrics reporting when field trials are forced.
-  if (command_line->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;
+  return is_reporting_enabled_callback_.Run();
 }
 
 void MetricsStateManager::ForceClientIdCreation() {
   if (!client_id_.empty())
     return;
 
   client_id_ = local_state_->GetString(prefs::kMetricsClientID);
   if (!client_id_.empty())
     return;
 
@@ skipping 55 matching lines @@
                                          kMaxLowEntropySize));
 #else
   return scoped_ptr<const base::FieldTrial::EntropyProvider>(
       new PermutedEntropyProvider(low_entropy_source_value,
                                   kMaxLowEntropySize));
 #endif
 }
 
 // static
 scoped_ptr<MetricsStateManager> MetricsStateManager::Create(
-    PrefService* local_state) {
+    PrefService* local_state,
+    const base::Callback<bool(void)>& is_reporting_enabled_callback) {
   scoped_ptr<MetricsStateManager> result;
   // Note: |instance_exists_| is updated in the constructor and destructor.
-  if (!instance_exists_)
-    result.reset(new MetricsStateManager(local_state));
+  if (!instance_exists_) {
+    result.reset(
+        new MetricsStateManager(local_state, is_reporting_enabled_callback));
+  }
   return result.Pass();
 }
 
 // static
 void MetricsStateManager::RegisterPrefs(PrefRegistrySimple* registry) {
   registry->RegisterBooleanPref(prefs::kMetricsResetIds, false);
   registry->RegisterStringPref(prefs::kMetricsClientID, std::string());
   registry->RegisterInt64Pref(prefs::kMetricsReportingEnabledTimestamp, 0);
   registry->RegisterIntegerPref(prefs::kMetricsLowEntropySource,
                                 kLowEntropySourceNotSet);
@@ skipping 46 matching lines @@
 
   DCHECK(client_id_.empty());
   DCHECK_EQ(kLowEntropySourceNotSet, low_entropy_source_);
 
   local_state_->ClearPref(prefs::kMetricsClientID);
   local_state_->ClearPref(prefs::kMetricsLowEntropySource);
   local_state_->ClearPref(prefs::kMetricsResetIds);
 }
 
 }  // namespace metrics