Add functionality for embedders to configure NQE

components/cronet/android/cronet_url_request_context_adapter.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/cronet/android/cronet_url_request_context_adapter.h"
 
 #include <limits.h>
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 656 matching lines @@
   // Explicitly disable the persister for Cronet to avoid persistence of dynamic
   // HPKP. This is a safety measure ensuring that nobody enables the persistence
   // of HPKP by specifying transport_security_persister_path in the future.
   context_builder.set_transport_security_persister_path(base::FilePath());
 
   // Disable net::CookieStore and net::ChannelIDService.
   context_builder.SetCookieAndChannelIdStores(nullptr, nullptr);
 
   if (config->enable_network_quality_estimator) {
     DCHECK(!network_quality_estimator_);
-    std::map<std::string, std::string> variation_params;
+
+    // NetworkQualityEstimator experiment dictionary name.
+    const char kNetworkQualityEstimatorFieldTrialName[] =

[mgersh, 2017/05/02 18:06:49]

Instead of duplicating this here, you could make it accessible from
url_request_context_config.h.

[tbansal1, 2017/06/28 14:19:54]

Obsolete.

+        "NetworkQualityEstimator";
+
+    // Network quality estimator configuration params.
+    std::map<std::string, std::string> network_quality_estimator_options;
+    const base::DictionaryValue* nqe_args = nullptr;
+
+    if (effective_experimental_options_ &&
+        effective_experimental_options_->GetDictionary(
+            kNetworkQualityEstimatorFieldTrialName, &nqe_args)) {

[xunjieli, 2017/05/02 17:56:34]

Can we move the parsing of NQE options to url_request_context_config.cc? The
reason is that we want to detect any unrecognized options at one place, so
Cronet's NetLog dumps can have a full picture of what's in effect.

[tbansal1, 2017/06/28 14:19:54]

Done.

+      for (base::DictionaryValue::Iterator it(*nqe_args); !it.IsAtEnd();
+           it.Advance()) {
+        std::string value_string;
+        bool value_string_available;
+        value_string_available = it.value().GetAsString(&value_string);
+        DCHECK(value_string_available);
+        network_quality_estimator_options.emplace(it.key(), value_string);
+      }
+    }
+
     // Configure network quality estimator: Specify the algorithm that should
-    // be used for computing the effective connection type. The algorithm
-    // is specified using the key-value pairs defined in
-    // //net/nqe/network_quality_estimator.cc.
-    // TODO(tbansal): Investigate a more robust way of configuring the network
-    // quality estimator.
-    variation_params["effective_connection_type_algorithm"] =
-        "TransportRTTOrDownstreamThroughput";
+    // be used for computing the effective connection type if it has not been
+    // specified by the embedder. The algorithm is specified using the
+    // key-value pairs defined in //net/nqe/network_quality_estimator.cc.
+    if (network_quality_estimator_options.find(
+            "effective_connection_type_algorithm") ==
+        network_quality_estimator_options.end()) {
+      network_quality_estimator_options.emplace(
+          "effective_connection_type_algorithm",
+          "TransportRTTOrDownstreamThroughput");
+    }
     network_quality_estimator_ = base::MakeUnique<net::NetworkQualityEstimator>(
-        std::unique_ptr<net::ExternalEstimateProvider>(), variation_params,
-        false, false, g_net_log.Get().net_log());
+        std::unique_ptr<net::ExternalEstimateProvider>(),
+        network_quality_estimator_options, false, false,
+        g_net_log.Get().net_log());
     // Set the socket performance watcher factory so that network quality
     // estimator is notified of socket performance metrics from TCP and QUIC.
     context_builder.set_socket_performance_watcher_factory(
         network_quality_estimator_->GetSocketPerformanceWatcherFactory());
     network_quality_estimator_->AddEffectiveConnectionTypeObserver(this);
     network_quality_estimator_->AddRTTAndThroughputEstimatesObserver(this);
 
     // Set up network quality prefs if the storage path is specified.
     if (!config->storage_path.empty()) {
       DCHECK(!network_qualities_prefs_manager_);
@@ skipping 474 matching lines @@
     JNIEnv* env,
     const JavaParamRef<jclass>& jcaller) {
   DCHECK(base::StatisticsRecorder::IsActive());
   std::vector<uint8_t> data;
   if (!HistogramManager::GetInstance()->GetDeltas(&data))
     return ScopedJavaLocalRef<jbyteArray>();
   return base::android::ToJavaByteArray(env, &data[0], data.size());
 }
 
 }  // namespace cronet