Remove Safebrowsing Rappor support

ios/chrome/browser/metrics/ios_chrome_metrics_services_manager_client.mm

Index: ios/chrome/browser/metrics/ios_chrome_metrics_services_manager_client.mm
diff --git a/ios/chrome/browser/metrics/ios_chrome_metrics_services_manager_client.mm b/ios/chrome/browser/metrics/ios_chrome_metrics_services_manager_client.mm
index f7b96d49a6a13852e2e2addae59a098065900deb..7c7340b50e1facb8468d0224c67b8b992b3d5196 100644
--- a/ios/chrome/browser/metrics/ios_chrome_metrics_services_manager_client.mm
+++ b/ios/chrome/browser/metrics/ios_chrome_metrics_services_manager_client.mm
@@ -94,11 +94,6 @@ IOSChromeMetricsServicesManagerClient::GetURLRequestContext() {
   return GetApplicationContext()->GetSystemURLRequestContext();
 }
 
-bool IOSChromeMetricsServicesManagerClient::IsSafeBrowsingEnabled(
-    const base::Closure& on_update_callback) {
-  return false;
-}
-
 bool IOSChromeMetricsServicesManagerClient::IsMetricsReportingEnabled() {
   return enabled_state_provider_->IsReportingEnabled();
 }