Read NQE prefs to network quality store under all cases

net/nqe/network_quality_estimator_params.h

Index: net/nqe/network_quality_estimator_params.h
diff --git a/net/nqe/network_quality_estimator_params.h b/net/nqe/network_quality_estimator_params.h
index 9f655168d0ff6eb69da1caf3b7c4e1fe0bee11e9..f9dcd0c0ba5fe673762560fd5de5bef8d55857b7 100644
--- a/net/nqe/network_quality_estimator_params.h
+++ b/net/nqe/network_quality_estimator_params.h
@@ -73,6 +73,11 @@ bool forced_effective_connection_type_set(
 EffectiveConnectionType forced_effective_connection_type(
     const std::map<std::string, std::string>& variation_params);
 
+// Returns true if reading from the persistent cache has been enabled via field
+// trial.
+bool persistent_cache_reading_enabled(
+    const std::map<std::string, std::string>& variation_params);
+
 }  // namespace internal
 
 }  // namespace nqe