Add a Rappor option in the settings page.

chrome/browser/metrics/metrics_services_manager.cc

Index: chrome/browser/metrics/metrics_services_manager.cc
diff --git a/chrome/browser/metrics/metrics_services_manager.cc b/chrome/browser/metrics/metrics_services_manager.cc
index f64ee5f86f4deaa9ef008a11648a61990a6815fc..44fad5949a1b78fe14d3b985fcfc4a6cf396f90d 100644
--- a/chrome/browser/metrics/metrics_services_manager.cc
+++ b/chrome/browser/metrics/metrics_services_manager.cc
@@ -18,6 +18,7 @@
 #include "chrome/installer/util/google_update_settings.h"
 #include "components/metrics/metrics_service.h"
 #include "components/metrics/metrics_state_manager.h"
+#include "components/rappor/rappor_pref_names.h"
 #include "components/rappor/rappor_service.h"
 
 #if defined(OS_CHROMEOS)
@@ -86,6 +87,15 @@ metrics::MetricsStateManager* MetricsServicesManager::GetMetricsStateManager() {
   return metrics_state_manager_.get();
 }
 
+bool MetricsServicesManager::IsRapporEnabled() const {
+  if (!local_state_->HasPrefPath(rappor::prefs::kRapporEnabled)) {
+    // For upgrading users, derive a default setting from safe browsing.
+    //bool sb_enabled = local_state_->GetBoolean(prefs::kSafeBrowsingEnabled);

[Steven Holte, 2015/02/06 00:15:46]

I'm not actually sure what the correct way to get this setting is, since I get
errors due to the pref not being registered.

Also need to handle propagating enterprise settings on metrics_enabled.

Additional question: Does prefs work for storing this enabled status on
Android/iOS?

[Alexei Svitkine (slow), 2015/02/06 16:43:33]

Yes, prefs work everywhere. You need to call RegisterBooleanPref somewhere on
the init path before this call to make it work.

e.g. see MetricsService::RegisterPrefs

+    local_state_->SetBoolean(rappor::prefs::kRapporEnabled, true);
+  }
+  return local_state_->GetBoolean(rappor::prefs::kRapporEnabled);
+}
+
 void MetricsServicesManager::UpdatePermissions(bool may_record,
                                                bool may_upload) {
   metrics::MetricsService* metrics = GetMetricsService();
@@ -114,8 +124,18 @@ void MetricsServicesManager::UpdatePermissions(bool may_record,
     metrics->Stop();
   }
 
-  rappor::RecordingLevel recording_level = may_record ?
-      rappor::FINE_LEVEL : rappor::RECORDING_DISABLED;
+  rappor::RecordingLevel recording_level = rappor::RECORDING_DISABLED;
+#if defined(GOOGLE_CHROME_BUILD)
+#if defined(OS_IOS) || defined(OS_ANDROID)
+  if (may_record) {
+    recording_level = rappor::FINE_LEVEL;
+  }
+#else  // defined(OS_IOS) || defined(OS_ANDROID)
+  if (IsRapporEnabled()) {
+    recording_level = may_record ? rappor::FINE_LEVEL : rappor::COARSE_LEVEL;
+  }
+#endif  // defined(OS_IOS) || defined(OS_ANDROID)
+#endif  // defined(GOOGLE_CHROME_BUILD)
   GetRapporService()->Update(recording_level, may_upload);
 }