Add functionality for embedders to configure NQE

components/cronet/url_request_context_config.cc

Index: components/cronet/url_request_context_config.cc
diff --git a/components/cronet/url_request_context_config.cc b/components/cronet/url_request_context_config.cc
index 16bd87fa42719aa48d981ff2977bd6e991edd141..f88a8765f8ac6d21c4ecc8778e29519a3f420215 100644
--- a/components/cronet/url_request_context_config.cc
+++ b/components/cronet/url_request_context_config.cc
@@ -79,6 +79,9 @@ const char kStaleDnsAllowOtherNetwork[] = "allow_other_network";
 const char kHostResolverRulesFieldTrialName[] = "HostResolverRules";
 const char kHostResolverRules[] = "host_resolver_rules";
 
+// NetworkQualityEstimator experiment dictionary name.
+const char kNetworkQualityEstimatorFieldTrialName[] = "NetworkQualityEstimator";
+
 // Disable IPv6 when on WiFi. This is a workaround for a known issue on certain
 // Android phones, and should not be necessary when not on one of those devices.
 // See https://crbug.com/696569 for details.
@@ -275,6 +278,13 @@ std::unique_ptr<base::DictionaryValue> ParseAndSetExperimentalOptions(
                                                  file_task_runner);
         }
       }
+    } else if (it.key() == kNetworkQualityEstimatorFieldTrialName) {
+      const base::DictionaryValue* nqe_args = nullptr;
+      if (!it.value().GetAsDictionary(&nqe_args)) {
+        LOG(ERROR) << "\"" << it.key() << "\" config params \"" << it.value()
+                   << "\" is not a dictionary value";
+        effective_experimental_options->Remove(it.key(), nullptr);
+      }
     } else {
       LOG(WARNING) << "Unrecognized Cronet experimental option \"" << it.key()
                    << "\" with params \"" << it.value();
@@ -353,12 +363,12 @@ URLRequestContextConfig::URLRequestContextConfig(
       load_disable_cache(load_disable_cache),
       storage_path(storage_path),
       user_agent(user_agent),
-      experimental_options(experimental_options),
       mock_cert_verifier(std::move(mock_cert_verifier)),
       enable_network_quality_estimator(enable_network_quality_estimator),
       bypass_public_key_pinning_for_local_trust_anchors(
           bypass_public_key_pinning_for_local_trust_anchors),
-      cert_verifier_data(cert_verifier_data) {}
+      cert_verifier_data(cert_verifier_data),
+      experimental_options(experimental_options) {}
 
 URLRequestContextConfig::~URLRequestContextConfig() {}