Revert of Seed NetworkQualityEstimator with default estimates. (patchset #6 id:160001 of https://codereview.chromium.org/1174263007/)

Reason for revert:
This is causing a perf regression because it increases the number of files containing a static initializer (network_quality_estimator.cc initializes a base::TimeDelta).

Original issue's description:
> Seed NetworkQualityEstimator with default estimates.
>
> When the browser starts, NetworkQualityEstimator has no
> observation and thus, cannot compute estimated network
> quality. This change populates the NetworkQualityEstimator
> observation buffers with default estimates that depend on
> current connection type.
>
> Default values are configured through field trial, which
> makes it easier to update them with time (or even target
> them based on country).
>
> BUG=472681
>
> Committed: https://crrev.com/c05c8745a17a915f10ab4e4c02e2c6c5f2eac96a
> Cr-Commit-Position: refs/heads/master@{#336074}

TBR=bengr@chromium.org,pauljensen@chromium.org,mmenke@chromium.org,tbansal@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=472681

Review URL: https://codereview.chromium.org/1208763002

Cr-Commit-Position: refs/heads/master@{#336088}

9 files changed, 33 insertions, 257 deletions

diff --git a/chrome/browser/io_thread.cc b/chrome/browser/io_thread.cc
index 15acb77..0dd9c0e 100644
--- a/chrome/browser/io_thread.cc
+++ b/chrome/browser/io_thread.cc
@@ -139,11 +139,6 @@ const char kSpdyFieldTrialSpdy31GroupNamePrefix[] = "Spdy31Enabled";
 const char kSpdyFieldTrialSpdy4GroupNamePrefix[] = "Spdy4Enabled";
 const char kSpdyFieldTrialParametrizedPrefix[] = "Parametrized";
 
-// Field trial for network quality estimator. Seeds RTT and downstream
-// throughput observations with values that correspond to the connection type
-// determined by the operating system.
-const char kNetworkQualityEstimatorFieldTrialName[] = "NetworkQualityEstimator";
-
 #if defined(OS_MACOSX) && !defined(OS_IOS)
 void ObserveKeychainEvents() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
@@ -646,11 +641,7 @@ void IOThread::Init() {
   globals_->system_network_delegate = chrome_network_delegate.Pass();
   globals_->host_resolver = CreateGlobalHostResolver(net_log_);
 
-  std::map<std::string, std::string> network_quality_estimator_params;
-  variations::GetVariationParams(kNetworkQualityEstimatorFieldTrialName,
-                                 &network_quality_estimator_params);
-  globals_->network_quality_estimator.reset(
-      new net::NetworkQualityEstimator(network_quality_estimator_params));
+  globals_->network_quality_estimator.reset(new net::NetworkQualityEstimator());
 
   // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466432
   // is fixed.
diff --git a/chrome/browser/io_thread.h b/chrome/browser/io_thread.h
index 1066a9b..689b11d 100644
--- a/chrome/browser/io_thread.h
+++ b/chrome/browser/io_thread.h
@@ -5,7 +5,6 @@
 #ifndef CHROME_BROWSER_IO_THREAD_H_
 #define CHROME_BROWSER_IO_THREAD_H_
 
-#include <map>
 #include <string>
 #include <vector>
 
diff --git a/components/data_reduction_proxy/core/browser/data_reduction_proxy_config_unittest.cc b/components/data_reduction_proxy/core/browser/data_reduction_proxy_config_unittest.cc
index 5233245..dbdc85c 100644
--- a/components/data_reduction_proxy/core/browser/data_reduction_proxy_config_unittest.cc
+++ b/components/data_reduction_proxy/core/browser/data_reduction_proxy_config_unittest.cc
@@ -4,7 +4,6 @@
 
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_config.h"
 
-#include <map>
 #include <vector>
 
 #include "base/command_line.h"
@@ -1222,11 +1221,7 @@ TEST_F(DataReductionProxyConfigTest, LoFiStatusTransition) {
 // Overrides net::NetworkQualityEstimator for testing.
 class TestNetworkQualityEstimator : public net::NetworkQualityEstimator {
  public:
-  explicit TestNetworkQualityEstimator(
-      const std::map<std::string, std::string>& variation_params)
-      : NetworkQualityEstimator(variation_params),
-        rtt_(base::TimeDelta()),
-        kbps_(0) {}
+  TestNetworkQualityEstimator() : rtt_(base::TimeDelta()), kbps_(0) {}
 
   ~TestNetworkQualityEstimator() override {}
 
@@ -1283,9 +1278,7 @@ TEST_F(DataReductionProxyConfigTest, AutoLoFiParams) {
   EXPECT_EQ(base::TimeDelta::FromSeconds(hysteresis_sec),
             config.auto_lofi_hysteresis_);
 
-  std::map<std::string, std::string> network_quality_estimator_params;
-  TestNetworkQualityEstimator test_network_quality_estimator(
-      network_quality_estimator_params);
+  TestNetworkQualityEstimator test_network_quality_estimator;
 
   // RTT is higher than threshold. Network is slow.
   test_network_quality_estimator.SetRtt(
diff --git a/net/base/network_quality.cc b/net/base/network_quality.cc
index a25c971..90f282d 100644
--- a/net/base/network_quality.cc
+++ b/net/base/network_quality.cc
@@ -8,12 +8,7 @@
 
 namespace net {
 
-const base::TimeDelta NetworkQuality::kInvalidRTT = base::TimeDelta::Max();
-
-const int32_t NetworkQuality::kInvalidThroughput = 0;
-
-NetworkQuality::NetworkQuality()
-    : NetworkQuality(kInvalidRTT, kInvalidThroughput) {
+NetworkQuality::NetworkQuality() : NetworkQuality(base::TimeDelta::Max(), 0) {
 }
 
 NetworkQuality::NetworkQuality(const base::TimeDelta& rtt,
diff --git a/net/base/network_quality.h b/net/base/network_quality.h
index b47e21c..315616f 100644
--- a/net/base/network_quality.h
+++ b/net/base/network_quality.h
@@ -16,14 +16,6 @@ namespace net {
 // estimated by the NetworkQualityEstimator.
 class NET_EXPORT_PRIVATE NetworkQuality {
  public:
-  // RTT is set to |kInvalidRTT| if a valid value is unavailable. Readers
-  // should discard RTT if it is set to |kInvalidRTT|.
-  static const base::TimeDelta kInvalidRTT;
-  // Throughput is set to |kInvalidThroughput| if a valid value is unavailable.
-  // Readers should discard throughput value if it is set to
-  // |kInvalidThroughput|.
-  static const int32_t kInvalidThroughput;
-
   NetworkQuality();
   // |rtt| is the estimate of the round trip time.
   // |downstream_throughput_kbps| is the estimate of the downstream throughput.
diff --git a/net/base/network_quality_estimator.cc b/net/base/network_quality_estimator.cc
index 9f37be0..9131f8f 100644
--- a/net/base/network_quality_estimator.cc
+++ b/net/base/network_quality_estimator.cc
@@ -13,9 +13,9 @@
 
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
-#include "base/strings/string_number_conversions.h"
 #include "net/base/load_timing_info.h"
 #include "net/base/net_util.h"
+#include "net/base/network_quality.h"
 #include "net/url_request/url_request.h"
 #include "url/gurl.h"
 
@@ -31,112 +31,29 @@ const size_t kMaximumObservationsBufferSize = 500;
 // in the NetworkQualityEstimator constructor.
 const int kHalfLifeSeconds = 60;
 
-// Name of the different connection types. Used for matching the connection
-// type to the variation parameters. Names must be in the same order as
-// NetworkChangeNotifier::ConnectionType enum.
-const char* const kConnectionTypeNames[] =
-    {"Unknown", "Ethernet", "WiFi", "2G", "3G", "4G", "None", "Bluetooth"};
-
-// Suffix of the name of the variation parameter that contains the default RTT
-// observation (in milliseconds). Complete name of the variation parameter
-// would be |ConnectionType|.|kDefaultRTTMsecObservationSuffix| where
-// |ConnectionType| is from |kConnectionTypeNames|. For example, variation
-// parameter for Wi-Fi would be "WiFi.DefaultMedianRTTMsec".
-const char kDefaultRTTMsecObservationSuffix[] = ".DefaultMedianRTTMsec";
-
-// Suffix of the name of the variation parameter that contains the default
-// downstream throughput observation (in Kbps).  Complete name of the variation
-// parameter would be |ConnectionType|.|kDefaultKbpsObservationSuffix| where
-// |ConnectionType| is from |kConnectionTypeNames|. For example, variation
-// parameter for Wi-Fi would be "WiFi.DefaultMedianKbps".
-const char kDefaultKbpsObservationSuffix[] = ".DefaultMedianKbps";
-
 }  // namespace
 
 namespace net {
 
-NetworkQualityEstimator::NetworkQualityEstimator(
-    const std::map<std::string, std::string>& variation_params)
-    : NetworkQualityEstimator(variation_params, false, false) {
+NetworkQualityEstimator::NetworkQualityEstimator()
+    : NetworkQualityEstimator(false, false) {
 }
 
 NetworkQualityEstimator::NetworkQualityEstimator(
-    const std::map<std::string, std::string>& variation_params,
     bool allow_local_host_requests_for_tests,
     bool allow_smaller_responses_for_tests)
     : allow_localhost_requests_(allow_local_host_requests_for_tests),
       allow_small_responses_(allow_smaller_responses_for_tests),
       last_connection_change_(base::TimeTicks::Now()),
       current_connection_type_(NetworkChangeNotifier::GetConnectionType()),
-      fastest_rtt_since_last_connection_change_(NetworkQuality::kInvalidRTT),
-      peak_kbps_since_last_connection_change_(
-          NetworkQuality::kInvalidThroughput) {
+      fastest_rtt_since_last_connection_change_(base::TimeDelta::Max()),
+      peak_kbps_since_last_connection_change_(0) {
   static_assert(kMinRequestDurationMicroseconds > 0,
                 "Minimum request duration must be > 0");
   static_assert(kHalfLifeSeconds > 0, "Half life duration must be > 0");
-  static_assert(arraysize(kConnectionTypeNames) ==
-                    NetworkChangeNotifier::CONNECTION_LAST + 1,
-                "ConnectionType name count should match");
-
-  ObtainOperatingParams(variation_params);
-  AddDefaultEstimates();
   NetworkChangeNotifier::AddConnectionTypeObserver(this);
 }
 
-void NetworkQualityEstimator::ObtainOperatingParams(
-    const std::map<std::string, std::string>& variation_params) {
-  DCHECK(thread_checker_.CalledOnValidThread());
-
-  for (size_t i = 0; i < arraysize(kConnectionTypeNames); ++i) {
-    int32_t variations_value = kMinimumRTTVariationParameterMsec - 1;
-    // Name of the parameter that holds the RTT value for this connection type.
-    std::string rtt_parameter_name =
-        std::string(kConnectionTypeNames[i])
-            .append(kDefaultRTTMsecObservationSuffix);
-    auto it = variation_params.find(rtt_parameter_name);
-    if (it != variation_params.end() && !it->second.empty() &&
-        base::StringToInt(it->second, &variations_value) &&
-        variations_value >= kMinimumRTTVariationParameterMsec) {
-      default_observations_[i] =
-          NetworkQuality(base::TimeDelta::FromMilliseconds(variations_value),
-                         default_observations_[i].downstream_throughput_kbps());
-    }
-
-    variations_value = kMinimumThroughputVariationParameterKbps - 1;
-    // Name of the parameter that holds the Kbps value for this connection
-    // type.
-    std::string kbps_parameter_name =
-        std::string(kConnectionTypeNames[i])
-            .append(kDefaultKbpsObservationSuffix);
-    it = variation_params.find(kbps_parameter_name);
-    if (it != variation_params.end() && !it->second.empty() &&
-        base::StringToInt(it->second, &variations_value) &&
-        variations_value >= kMinimumThroughputVariationParameterKbps) {
-      default_observations_[i] =
-          NetworkQuality(default_observations_[i].rtt(), variations_value);
-    }
-  }
-}
-
-void NetworkQualityEstimator::AddDefaultEstimates() {
-  DCHECK(thread_checker_.CalledOnValidThread());
-
-  if (default_observations_[current_connection_type_].rtt() !=
-      NetworkQuality::kInvalidRTT) {
-    rtt_msec_observations_.AddObservation(Observation(
-        default_observations_[current_connection_type_].rtt().InMilliseconds(),
-        base::TimeTicks::Now()));
-  }
-
-  if (default_observations_[current_connection_type_]
-          .downstream_throughput_kbps() != NetworkQuality::kInvalidThroughput) {
-    kbps_observations_.AddObservation(
-        Observation(default_observations_[current_connection_type_]
-                        .downstream_throughput_kbps(),
-                    base::TimeTicks::Now()));
-  }
-}
-
 NetworkQualityEstimator::~NetworkQualityEstimator() {
   DCHECK(thread_checker_.CalledOnValidThread());
   NetworkChangeNotifier::RemoveConnectionTypeObserver(this);
@@ -229,8 +146,7 @@ void NetworkQualityEstimator::NotifyDataReceived(
 void NetworkQualityEstimator::OnConnectionTypeChanged(
     NetworkChangeNotifier::ConnectionType type) {
   DCHECK(thread_checker_.CalledOnValidThread());
-  if (fastest_rtt_since_last_connection_change_ !=
-      NetworkQuality::kInvalidRTT) {
+  if (fastest_rtt_since_last_connection_change_ != base::TimeDelta::Max()) {
     switch (current_connection_type_) {
       case NetworkChangeNotifier::CONNECTION_UNKNOWN:
         UMA_HISTOGRAM_TIMES("NQE.FastestRTT.Unknown",
@@ -270,8 +186,7 @@ void NetworkQualityEstimator::OnConnectionTypeChanged(
     }
   }
 
-  if (peak_kbps_since_last_connection_change_ !=
-      NetworkQuality::kInvalidThroughput) {
+  if (peak_kbps_since_last_connection_change_) {
     switch (current_connection_type_) {
       case NetworkChangeNotifier::CONNECTION_UNKNOWN:
         UMA_HISTOGRAM_COUNTS("NQE.PeakKbps.Unknown",
@@ -312,13 +227,11 @@ void NetworkQualityEstimator::OnConnectionTypeChanged(
   }
 
   last_connection_change_ = base::TimeTicks::Now();
-  peak_kbps_since_last_connection_change_ = NetworkQuality::kInvalidThroughput;
-  fastest_rtt_since_last_connection_change_ = NetworkQuality::kInvalidRTT;
+  peak_kbps_since_last_connection_change_ = 0;
+  fastest_rtt_since_last_connection_change_ = base::TimeDelta::Max();
   kbps_observations_.Clear();
   rtt_msec_observations_.Clear();
   current_connection_type_ = type;
-
-  AddDefaultEstimates();
 }
 
 NetworkQuality NetworkQualityEstimator::GetPeakEstimate() const {
diff --git a/net/base/network_quality_estimator.h b/net/base/network_quality_estimator.h
index b8605d8..025ce2c 100644
--- a/net/base/network_quality_estimator.h
+++ b/net/base/network_quality_estimator.h
@@ -8,7 +8,6 @@
 #include <stdint.h>
 
 #include <deque>
-#include <map>
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
@@ -16,10 +15,11 @@
 #include "base/time/time.h"
 #include "net/base/net_export.h"
 #include "net/base/network_change_notifier.h"
-#include "net/base/network_quality.h"
 
 namespace net {
 
+class NetworkQuality;
+
 // NetworkQualityEstimator provides network quality estimates (quality of the
 // full paths to all origins that have been connected to).
 // The estimates are based on the observed organic traffic.
@@ -32,10 +32,7 @@ class NET_EXPORT_PRIVATE NetworkQualityEstimator
     : public NetworkChangeNotifier::ConnectionTypeObserver {
  public:
   // Creates a new NetworkQualityEstimator.
-  // |variation_params| is the map containing all field trial parameters
-  // related to NetworkQualityEstimator field trial.
-  explicit NetworkQualityEstimator(
-      const std::map<std::string, std::string>& variation_params);
+  NetworkQualityEstimator();
 
   ~NetworkQualityEstimator() override;
 
@@ -67,7 +64,6 @@ class NET_EXPORT_PRIVATE NetworkQualityEstimator
   FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest,
                            TestPeakKbpsFastestRTTUpdates);
   FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, TestAddObservation);
-  FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, ObtainOperatingParams);
   FRIEND_TEST_ALL_PREFIXES(URLRequestTestHTTP, NetworkQualityEstimator);
   FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest,
                            PercentileSameTimestamps);
@@ -137,8 +133,6 @@ class NET_EXPORT_PRIVATE NetworkQualityEstimator
 
    private:
     FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, StoreObservations);
-    FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest,
-                             ObtainOperatingParams);
 
     // Computes the weighted observations and stores them in
     // |weighted_observations| sorted by ascending |WeightedObservation.value|.
@@ -170,19 +164,10 @@ class NET_EXPORT_PRIVATE NetworkQualityEstimator
   // throughput is computed.
   static const int kMinRequestDurationMicroseconds = 1000;
 
-  // Minimum valid value of the variation parameter that holds RTT (in
-  // milliseconds) values.
-  static const int kMinimumRTTVariationParameterMsec = 1;
-
-  // Minimum valid value of the variation parameter that holds throughput (in
-  // kbps) values.
-  static const int kMinimumThroughputVariationParameterKbps = 1;
-
   // Construct a NetworkQualityEstimator instance allowing for test
-  // configuration. Registers for network type change notifications so estimates
-  // can be kept network specific.
-  // |variation_params| is the map containing all field trial parameters for the
-  // network quality estimator field trial.
+  // configuration.
+  // Registers for network type change notifications so estimates can be kept
+  // network specific.
   // |allow_local_host_requests_for_tests| should only be true when testing
   // against local HTTP server and allows the requests to local host to be
   // used for network quality estimation.
@@ -190,18 +175,8 @@ class NET_EXPORT_PRIVATE NetworkQualityEstimator
   // against local HTTP server and allows the responses smaller than
   // |kMinTransferSizeInBytes| or shorter than |kMinRequestDurationMicroseconds|
   // to be used for network quality estimation.
-  NetworkQualityEstimator(
-      const std::map<std::string, std::string>& variation_params,
-      bool allow_local_host_requests_for_tests,
-      bool allow_smaller_responses_for_tests);
-
-  // Obtains operating parameters from the field trial parameters.
-  void ObtainOperatingParams(
-      const std::map<std::string, std::string>& variation_params);
-
-  // Adds the default median RTT and downstream throughput estimate for the
-  // current connection type to the observation buffer.
-  void AddDefaultEstimates();
+  NetworkQualityEstimator(bool allow_local_host_requests_for_tests,
+                          bool allow_smaller_responses_for_tests);
 
   // Returns the maximum size of the observation buffer.
   // Used for testing.
@@ -255,12 +230,6 @@ class NET_EXPORT_PRIVATE NetworkQualityEstimator
   // Buffer that holds RTT (in milliseconds) observations sorted by timestamp.
   ObservationBuffer rtt_msec_observations_;
 
-  // Default network quality observations obtained from the network quality
-  // estimator field trial parameters. The observations are indexed by
-  // ConnectionType.
-  NetworkQuality
-      default_observations_[NetworkChangeNotifier::CONNECTION_LAST + 1];
-
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(NetworkQualityEstimator);
diff --git a/net/base/network_quality_estimator_unittest.cc b/net/base/network_quality_estimator_unittest.cc
index ec61b44..c1955ec4 100644
--- a/net/base/network_quality_estimator_unittest.cc
+++ b/net/base/network_quality_estimator_unittest.cc
@@ -5,7 +5,6 @@
 #include "net/base/network_quality_estimator.h"
 
 #include <limits>
-#include <map>
 
 #include "base/basictypes.h"
 #include "base/logging.h"
@@ -31,13 +30,11 @@ TEST(NetworkQualityEstimatorTest, DISABLED_TestPeakKbpsFastestRTTUpdates) {
   ASSERT_TRUE(embedded_test_server.InitializeAndWaitUntilReady());
 
   // Enable requests to local host to be used for network quality estimation.
-  std::map<std::string, std::string> variation_params;
-  NetworkQualityEstimator estimator(variation_params, true, true);
+  NetworkQualityEstimator estimator(true, true);
   {
     NetworkQuality network_quality = estimator.GetPeakEstimate();
-    EXPECT_EQ(NetworkQuality::kInvalidRTT, network_quality.rtt());
-    EXPECT_EQ(NetworkQuality::kInvalidThroughput,
-              network_quality.downstream_throughput_kbps());
+    EXPECT_EQ(network_quality.rtt(), base::TimeDelta::Max());
+    EXPECT_EQ(network_quality.downstream_throughput_kbps(), 0);
   }
 
   TestDelegate test_delegate;
@@ -72,9 +69,8 @@ TEST(NetworkQualityEstimatorTest, DISABLED_TestPeakKbpsFastestRTTUpdates) {
     NetworkQuality network_quality = estimator.GetPeakEstimate();
     EXPECT_EQ(estimator.current_connection_type_,
               NetworkChangeNotifier::ConnectionType::CONNECTION_WIFI);
-    EXPECT_EQ(NetworkQuality::kInvalidRTT, network_quality.rtt());
-    EXPECT_EQ(NetworkQuality::kInvalidThroughput,
-              network_quality.downstream_throughput_kbps());
+    EXPECT_EQ(network_quality.rtt(), base::TimeDelta::Max());
+    EXPECT_EQ(network_quality.downstream_throughput_kbps(), 0);
   }
 }
 
@@ -84,8 +80,7 @@ TEST(NetworkQualityEstimatorTest, StoreObservations) {
       base::FilePath(FILE_PATH_LITERAL("net/data/url_request_unittest")));
   ASSERT_TRUE(embedded_test_server.InitializeAndWaitUntilReady());
 
-  std::map<std::string, std::string> variation_params;
-  NetworkQualityEstimator estimator(variation_params, true, true);
+  NetworkQualityEstimator estimator(true, true);
   TestDelegate test_delegate;
   TestURLRequestContext context(false);
 
@@ -131,8 +126,7 @@ TEST(NetworkQualityEstimatorTest, StoreObservations) {
 // the same timestamp. Kbps percentiles must be in decreasing order. RTT
 // percentiles must be in increasing order.
 TEST(NetworkQualityEstimatorTest, PercentileSameTimestamps) {
-  std::map<std::string, std::string> variation_params;
-  NetworkQualityEstimator estimator(variation_params);
+  NetworkQualityEstimator estimator;
   base::TimeTicks now = base::TimeTicks::Now();
 
   // Network quality should be unavailable when no observations are available.
@@ -180,8 +174,7 @@ TEST(NetworkQualityEstimatorTest, PercentileSameTimestamps) {
 // much more heavily than older samples. Kbps percentiles must be in decreasing
 // order. RTT percentiles must be in increasing order.
 TEST(NetworkQualityEstimatorTest, PercentileDifferentTimestamps) {
-  std::map<std::string, std::string> variation_params;
-  NetworkQualityEstimator estimator(variation_params);
+  NetworkQualityEstimator estimator;
   base::TimeTicks now = base::TimeTicks::Now();
   base::TimeTicks very_old = base::TimeTicks::UnixEpoch();
 
@@ -225,12 +218,10 @@ TEST(NetworkQualityEstimatorTest, ComputedPercentiles) {
       base::FilePath(FILE_PATH_LITERAL("net/data/url_request_unittest")));
   ASSERT_TRUE(embedded_test_server.InitializeAndWaitUntilReady());
 
-  std::map<std::string, std::string> variation_params;
-  NetworkQualityEstimator estimator(variation_params, true, true);
+  NetworkQualityEstimator estimator(true, true);
   NetworkQuality network_quality = estimator.GetPeakEstimate();
-  EXPECT_EQ(NetworkQuality::kInvalidRTT, network_quality.rtt());
-  EXPECT_EQ(NetworkQuality::kInvalidThroughput,
-            network_quality.downstream_throughput_kbps());
+  EXPECT_EQ(network_quality.rtt(), base::TimeDelta::Max());
+  EXPECT_EQ(network_quality.downstream_throughput_kbps(), 0);
 
   TestDelegate test_delegate;
   TestURLRequestContext context(false);
@@ -269,70 +260,4 @@ TEST(NetworkQualityEstimatorTest, ComputedPercentiles) {
   }
 }
 
-// http://crbug.com/504058
-#if !defined(OS_WIN)
-TEST(NetworkQualityEstimatorTest, ObtainOperatingParams) {
-  std::map<std::string, std::string> variation_params;
-  variation_params["Unknown.DefaultMedianKbps"] = "100";
-  variation_params["WiFi.DefaultMedianKbps"] = "200";
-  variation_params["2G.DefaultMedianKbps"] = "300";
-
-  variation_params["Unknown.DefaultMedianRTTMsec"] = "1000";
-  variation_params["WiFi.DefaultMedianRTTMsec"] = "2000";
-  // Negative variation value should not be used.
-  variation_params["2G.DefaultMedianRTTMsec"] = "-5";
-
-  NetworkQualityEstimator estimator(variation_params, true, true);
-  EXPECT_EQ(1U, estimator.kbps_observations_.Size());
-  EXPECT_EQ(1U, estimator.rtt_msec_observations_.Size());
-  NetworkQuality network_quality;
-  EXPECT_TRUE(estimator.GetEstimate(&network_quality));
-  EXPECT_EQ(100, network_quality.downstream_throughput_kbps());
-  EXPECT_EQ(base::TimeDelta::FromMilliseconds(1000), network_quality.rtt());
-  auto it = estimator.kbps_observations_.observations_.begin();
-  EXPECT_EQ(100, (*it).value);
-  it = estimator.rtt_msec_observations_.observations_.begin();
-  EXPECT_EQ(1000, (*it).value);
-
-  // Simulate network change to Wi-Fi.
-  estimator.OnConnectionTypeChanged(
-      NetworkChangeNotifier::ConnectionType::CONNECTION_WIFI);
-  EXPECT_EQ(1U, estimator.kbps_observations_.Size());
-  EXPECT_EQ(1U, estimator.rtt_msec_observations_.Size());
-  EXPECT_TRUE(estimator.GetEstimate(&network_quality));
-  EXPECT_EQ(200, network_quality.downstream_throughput_kbps());
-  EXPECT_EQ(base::TimeDelta::FromMilliseconds(2000), network_quality.rtt());
-  it = estimator.kbps_observations_.observations_.begin();
-  EXPECT_EQ(200, (*it).value);
-  it = estimator.rtt_msec_observations_.observations_.begin();
-  EXPECT_EQ(2000, (*it).value);
-
-  // Peak network quality should not be affected by the network quality
-  // estimator field trial.
-  EXPECT_EQ(NetworkQuality::kInvalidRTT,
-            estimator.fastest_rtt_since_last_connection_change_);
-  EXPECT_EQ(NetworkQuality::kInvalidThroughput,
-            estimator.peak_kbps_since_last_connection_change_);
-
-  // Simulate network change to 2G. Only the Kbps default estimate should be
-  // available.
-  estimator.OnConnectionTypeChanged(
-      NetworkChangeNotifier::ConnectionType::CONNECTION_2G);
-  EXPECT_EQ(1U, estimator.kbps_observations_.Size());
-  EXPECT_EQ(0U, estimator.rtt_msec_observations_.Size());
-  // For GetEstimate() to return true, at least one observation must be
-  // available for both RTT and downstream throughput.
-  EXPECT_FALSE(estimator.GetEstimate(&network_quality));
-  it = estimator.kbps_observations_.observations_.begin();
-  EXPECT_EQ(300, (*it).value);
-
-  // Simulate network change to 3G. Default estimates should be unavailable.
-  estimator.OnConnectionTypeChanged(
-      NetworkChangeNotifier::ConnectionType::CONNECTION_3G);
-  EXPECT_FALSE(estimator.GetEstimate(&network_quality));
-  EXPECT_EQ(0U, estimator.kbps_observations_.Size());
-  EXPECT_EQ(0U, estimator.rtt_msec_observations_.Size());
-}
-#endif  // !defined(OS_WIN)
-
 }  // namespace net
diff --git a/net/url_request/url_request_unittest.cc b/net/url_request/url_request_unittest.cc
index 1f57487..11e19d9 100644
--- a/net/url_request/url_request_unittest.cc
+++ b/net/url_request/url_request_unittest.cc
@@ -4077,8 +4077,7 @@ TEST_F(URLRequestTestHTTP, GetZippedTest) {
 TEST_F(URLRequestTestHTTP, NetworkQualityEstimator) {
   ASSERT_TRUE(test_server_.Start());
   // Enable requests to local host to be used for network quality estimation.
-  std::map<std::string, std::string> variation_params;
-  NetworkQualityEstimator estimator(variation_params, true, true);
+  NetworkQualityEstimator estimator(true, true);
 
   TestDelegate d;
   TestNetworkDelegate network_delegate;  // Must outlive URLRequest.