Remove unnecessary DCHECK in BucketOverlapsInterval().

components/data_reduction_proxy/core/browser/data_usage_store.cc

Index: components/data_reduction_proxy/core/browser/data_usage_store.cc
diff --git a/components/data_reduction_proxy/core/browser/data_usage_store.cc b/components/data_reduction_proxy/core/browser/data_usage_store.cc
index ed8b6cf7f1ca775169009a8101ab4db1918f9177..98bcbbd0ed433bf750933983259f567349dc910b 100644
--- a/components/data_reduction_proxy/core/browser/data_usage_store.cc
+++ b/components/data_reduction_proxy/core/browser/data_usage_store.cc
@@ -225,7 +225,6 @@ bool DataUsageStore::BucketOverlapsInterval(
     const base::Time& start_interval,
     const base::Time& end_interval) {
   DCHECK(!bucket_last_updated.is_null());
-  DCHECK(!start_interval.is_null());
   DCHECK(!end_interval.is_null());
   DCHECK_LE(start_interval, end_interval);