Create feature and enable data collection for Data Saver site breakdown

components/data_reduction_proxy/core/common/data_reduction_proxy_features.cc

Index: components/data_reduction_proxy/core/common/data_reduction_proxy_features.cc
diff --git a/components/data_reduction_proxy/core/common/data_reduction_proxy_features.cc b/components/data_reduction_proxy/core/common/data_reduction_proxy_features.cc
index 8e7e96ee4b7ffb96bb2de32924aa668ff6543615..6e09db8dc845b02b47c7f01f1015ec540b76c932 100644
--- a/components/data_reduction_proxy/core/common/data_reduction_proxy_features.cc
+++ b/components/data_reduction_proxy/core/common/data_reduction_proxy_features.cc
@@ -12,5 +12,9 @@ namespace features {
 const base::Feature kDataReductionMainMenu{"DataReductionProxyMainMenu",
                                            base::FEATURE_DISABLED_BY_DEFAULT};
 
+// Enables the site breakdown on the Data Reduction Proxy settings page.
+const base::Feature kDataReductionSiteBreakdown{
+    "DataReductionProxySiteBreakdown", base::FEATURE_DISABLED_BY_DEFAULT};
+
 }  // namespace features
 }  // namespace data_reduction_proxy