Expose RTT and downlink bandwidth using experimental Javascript API

content/browser/net_info_browsertest.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 "base/command_line.h"
 #include "base/run_loop.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/test/histogram_tester.h"
 #include "build/build_config.h"
 #include "content/browser/net/network_quality_observer_impl.h"
@@ skipping 127 matching lines @@
 
   // Open the same page in a new window on the same process.
   EXPECT_TRUE(ExecuteScript(shell(), "window.open(\"net_info.html\")"));
 
   // The network state should not have reinitialized to what it was when opening
   // the first window (online).
   EXPECT_FALSE(RunScriptExtractBool("getOnLine()"));
 }
 
 // Make sure the changes in the network quality are notified to the render
-// thread.
+// thread, and the changed network quality is accessible via Javascript API.
 IN_PROC_BROWSER_TEST_F(NetInfoBrowserTest, NetworkQualityChangeNotified) {
   base::HistogramTester histogram_tester;
   net::TestNetworkQualityEstimator estimator;
+  estimator.SuppressNotificationsForTesting();
   NetworkQualityObserverImpl impl(&estimator);
+
+  net::nqe::internal::NetworkQuality network_quality_1(
+      base::TimeDelta::FromSeconds(1), base::TimeDelta::FromSeconds(2), 300);
   estimator.NotifyObserversOfRTTOrThroughputEstimatesComputed(
-      net::nqe::internal::NetworkQuality(base::TimeDelta::FromSeconds(1),
-                                         base::TimeDelta::FromSeconds(2), 3));
-
+      network_quality_1);
   NavigateToURL(shell(), content::GetTestUrl("", "net_info.html"));
 
+  base::RunLoop().RunUntilIdle();
   FetchHistogramsFromChildProcesses();
   EXPECT_FALSE(
       histogram_tester.GetAllSamples("NQE.RenderThreadNotified").empty());
+
+  EXPECT_EQ(network_quality_1.transport_rtt().InMilliseconds(),
+            RunScriptExtractDouble("getRtt()"));
+  EXPECT_EQ(
+      static_cast<double>(network_quality_1.downstream_throughput_kbps()) /
+          1000,
+      RunScriptExtractDouble("getDownlink()"));
+
+  // Verify that the network quality change is accessible via Javascript API.
+  net::nqe::internal::NetworkQuality network_quality_2(
+      base::TimeDelta::FromSeconds(10), base::TimeDelta::FromSeconds(20), 3000);
+  estimator.NotifyObserversOfRTTOrThroughputEstimatesComputed(
+      network_quality_2);
+  base::RunLoop().RunUntilIdle();
+  EXPECT_EQ(network_quality_2.transport_rtt().InMilliseconds(),
+            RunScriptExtractDouble("getRtt()"));
+  EXPECT_EQ(
+      static_cast<double>(network_quality_2.downstream_throughput_kbps()) /
+          1000,
+      RunScriptExtractDouble("getDownlink()"));
+}
+
+// Make sure the changes in the network quality are rounded to the nearest
+// 25 milliseconds or 25 kbps.
+IN_PROC_BROWSER_TEST_F(NetInfoBrowserTest, NetworkQualityChangeRounded) {
+  base::HistogramTester histogram_tester;
+  net::TestNetworkQualityEstimator estimator;
+  estimator.SuppressNotificationsForTesting();
+  NetworkQualityObserverImpl impl(&estimator);
+
+  // Verify that the network quality is rounded properly.
+  net::nqe::internal::NetworkQuality network_quality_1(
+      base::TimeDelta::FromMilliseconds(123),

[bengr, 2017/05/12 19:09:54]

I would also test value of -1 since that's how you initialize. 0 and max int
might be good too.

[tbansal1, 2017/05/12 22:18:17]

Added -1 and 0 check.

+      base::TimeDelta::FromMilliseconds(212), 303);
+  estimator.NotifyObserversOfRTTOrThroughputEstimatesComputed(
+      network_quality_1);
+  NavigateToURL(shell(), content::GetTestUrl("", "net_info.html"));
+  base::RunLoop().RunUntilIdle();
+  EXPECT_EQ(200, RunScriptExtractDouble("getRtt()"));
+  EXPECT_EQ(0.300, RunScriptExtractDouble("getDownlink()"));
+
+  net::nqe::internal::NetworkQuality network_quality_2(
+      base::TimeDelta::FromMilliseconds(123),
+      base::TimeDelta::FromMilliseconds(1217), 1317);
+  estimator.NotifyObserversOfRTTOrThroughputEstimatesComputed(
+      network_quality_2);
+  base::RunLoop().RunUntilIdle();
+  EXPECT_EQ(1225, RunScriptExtractDouble("getRtt()"));
+  EXPECT_EQ(1.325, RunScriptExtractDouble("getDownlink()"));
+}
+
+// Make sure the minor changes in the network quality are not notified.

[bengr, 2017/05/12 19:09:54]

Say how minor is minor, or at least say how to determine that.

[tbansal1, 2017/05/12 22:18:17]

Done.

+IN_PROC_BROWSER_TEST_F(NetInfoBrowserTest, NetworkQualityChangeNotNotified) {
+  base::HistogramTester histogram_tester;
+  net::TestNetworkQualityEstimator estimator;
+  estimator.SuppressNotificationsForTesting();
+  NetworkQualityObserverImpl impl(&estimator);
+
+  // Verify that the network quality is rounded properly.
+  net::nqe::internal::NetworkQuality network_quality_1(
+      base::TimeDelta::FromMilliseconds(1123),
+      base::TimeDelta::FromMilliseconds(1212), 1303);
+  estimator.NotifyObserversOfRTTOrThroughputEstimatesComputed(
+      network_quality_1);
+  NavigateToURL(shell(), content::GetTestUrl("", "net_info.html"));
+  base::RunLoop().RunUntilIdle();
+  EXPECT_EQ(1200, RunScriptExtractDouble("getRtt()"));
+  EXPECT_EQ(1.300, RunScriptExtractDouble("getDownlink()"));
+
+  // All the 3 metrics change by less than 10%. So, the observers are not
+  // notified.
+  net::nqe::internal::NetworkQuality network_quality_2(
+      base::TimeDelta::FromMilliseconds(1223),
+      base::TimeDelta::FromMilliseconds(1312), 1403);
+  estimator.NotifyObserversOfRTTOrThroughputEstimatesComputed(
+      network_quality_2);
+  base::RunLoop().RunUntilIdle();
+  EXPECT_EQ(1200, RunScriptExtractDouble("getRtt()"));
+  EXPECT_EQ(1.300, RunScriptExtractDouble("getDownlink()"));
+
+  // Transport RTT has changed by more than 10% from the last notified value of
+  // |network_quality_1|. The observers should be notified.
+  net::nqe::internal::NetworkQuality network_quality_3(
+      base::TimeDelta::FromMilliseconds(1223),
+      base::TimeDelta::FromMilliseconds(2312), 1403);
+  estimator.NotifyObserversOfRTTOrThroughputEstimatesComputed(
+      network_quality_3);
+  base::RunLoop().RunUntilIdle();
+  EXPECT_EQ(2300, RunScriptExtractDouble("getRtt()"));
+  EXPECT_EQ(1.400, RunScriptExtractDouble("getDownlink()"));
 }
 
 }  // namespace content