Domain Reliability: Add more upload-related histograms.

components/domain_reliability/context_manager.h

Index: components/domain_reliability/context_manager.h
diff --git a/components/domain_reliability/context_manager.h b/components/domain_reliability/context_manager.h
index 3d3aaead3ea6f7e817026f95391a88437d76391b..c9b1d93adc07da1f680dcc22ec2d2b608f6aba94 100644
--- a/components/domain_reliability/context_manager.h
+++ b/components/domain_reliability/context_manager.h
@@ -13,6 +13,7 @@
 #include <unordered_set>
 
 #include "base/macros.h"
+#include "base/time/time.h"
 #include "base/values.h"
 #include "components/domain_reliability/beacon.h"
 #include "components/domain_reliability/config.h"
@@ -72,6 +73,8 @@ class DOMAIN_RELIABILITY_EXPORT DomainReliabilityContextManager {
   // context manager knows they are allowed to set a config again later.
   std::unordered_set<std::string> removed_contexts_;
 
+  base::TimeTicks last_routed_beacon_time_;
+
   DISALLOW_COPY_AND_ASSIGN(DomainReliabilityContextManager);
 };