Use NetworkTrafficAnnotation in URLRequestContext UMA logging

net/url_request/url_request_context.cc

Index: net/url_request/url_request_context.cc
diff --git a/net/url_request/url_request_context.cc b/net/url_request/url_request_context.cc
index 1de1aa7922a69baf2f9d74445513dc52a3538a1f..ce0676e8316899bba1e496106c9a4fb799b870a5 100644
--- a/net/url_request/url_request_context.cc
+++ b/net/url_request/url_request_context.cc
@@ -127,6 +127,9 @@ void URLRequestContext::InsertURLRequest(const URLRequest* request) const {
     largest_outstanding_requests_count_seen_ = url_requests_.size();
     UMA_HISTOGRAM_COUNTS_1M("Net.URLRequestContext.OutstandingRequests",
                             largest_outstanding_requests_count_seen_);
+    UMA_HISTOGRAM_SPARSE_SLOWLY(
+        "Net.URLRequestContext.OutstandingRequests.Type",
+        request->traffic_annotation().unique_id_hash_code);
   }
 }