Create feature and enable data collection for Data Saver site breakdown

components/data_reduction_proxy/core/browser/data_usage_store.h

Index: components/data_reduction_proxy/core/browser/data_usage_store.h
diff --git a/components/data_reduction_proxy/core/browser/data_usage_store.h b/components/data_reduction_proxy/core/browser/data_usage_store.h
index c346408374be284c09a1e2c6ad1288bc2dd4242a..9ef594a55bd80c7e629cbd616da91690610ec40c 100644
--- a/components/data_reduction_proxy/core/browser/data_usage_store.h
+++ b/components/data_reduction_proxy/core/browser/data_usage_store.h
@@ -21,6 +21,12 @@ namespace data_reduction_proxy {
 class DataStore;
 class DataUsageBucket;
 
+// Time interval for each DataUsageBucket.
+constexpr int kDataUsageBucketLengthInMinutes = 15;
+
+// Number of days for which to maintain data usage history.
+constexpr int kDataUsageHistoryNumDays = 60;
+
 // Store for detailed data usage stats. Data usage from every
 // |kDataUsageBucketLengthMins| interval is stored in a DataUsageBucket.
 class DataUsageStore {