Add a finch trial param to disable QUIC when connection times out with open streams

BUG=571098

Review URL: https://codereview.chromium.org/1603203002

Cr-Commit-Position: refs/heads/master@{#370806}

chrome/browser/io_thread.cc

@@ -1144,6 +1144,8 @@ void IOThread::InitializeNetworkSessionParamsFromGlobals(
   globals.enable_brotli.CopyToIfSet(&params->enable_brotli);
 
   globals.enable_quic.CopyToIfSet(&params->enable_quic);
+  globals.disable_quic_on_timeout_with_open_streams.CopyToIfSet(
+    &params->disable_quic_on_timeout_with_open_streams);
   globals.enable_quic_for_proxies.CopyToIfSet(&params->enable_quic_for_proxies);
   globals.quic_always_require_handshake_confirmation.CopyToIfSet(
       &params->quic_always_require_handshake_confirmation);
@@ -1268,6 +1270,8 @@ void IOThread::ConfigureQuicGlobals(
   bool enable_quic = ShouldEnableQuic(command_line, quic_trial_group,
                                       quic_allowed_by_policy);
   globals->enable_quic.set(enable_quic);
+  globals->disable_quic_on_timeout_with_open_streams.set(
+    ShouldDisableQuicWhenConnectionTimesOutWithOpenStreams(quic_trial_params));
   bool enable_quic_for_proxies = ShouldEnableQuicForProxies(
       command_line, quic_trial_group, quic_allowed_by_policy);
   globals->enable_quic_for_proxies.set(enable_quic_for_proxies);
@@ -1366,6 +1370,14 @@ void IOThread::ConfigureQuicGlobals(
   }
 }
 
+bool IOThread::ShouldDisableQuicWhenConnectionTimesOutWithOpenStreams(
+    const VariationParameters& quic_trial_params) {
+  return base::LowerCaseEqualsASCII(
+    GetVariationParam(quic_trial_params,
+      "disable_quic_on_timeout_with_open_streams"),
+      "true");
+}
+
 bool IOThread::ShouldEnableQuic(const base::CommandLine& command_line,
                                 base::StringPiece quic_trial_group,
                                 bool quic_allowed_by_policy) {

chrome/browser/io_thread.h

@@ -219,6 +219,7 @@ class IOThread : public content::BrowserThreadDelegate {
     Optional<bool> enable_brotli;
 
     Optional<bool> enable_quic;
+    Optional<bool> disable_quic_on_timeout_with_open_streams;
     Optional<bool> enable_quic_for_proxies;
     Optional<bool> enable_quic_port_selection;
     Optional<bool> quic_always_require_handshake_confirmation;
@@ -371,6 +372,11 @@ class IOThread : public content::BrowserThreadDelegate {
       bool quic_allowed_by_policy,
       Globals* globals);
 
+  // Returns true if QUIC should be disabled when a connection times out with
+  // open streams.
+  static bool ShouldDisableQuicWhenConnectionTimesOutWithOpenStreams(
+      const VariationParameters& quic_trial_params);
+
   // Returns true if QUIC should be enabled, either as a result
   // of a field trial or a command line flag.
   static bool ShouldEnableQuic(

chrome/browser/io_thread_unittest.cc

@@ -213,6 +213,7 @@ TEST_F(IOThreadTest, EnableQuicFromFieldTrialGroup) {
   net::HttpNetworkSession::Params params;
   InitializeNetworkSessionParams(&params);
   EXPECT_TRUE(params.enable_quic);
+  EXPECT_FALSE(params.disable_quic_on_timeout_with_open_streams);
   EXPECT_TRUE(params.enable_quic_for_proxies);
   EXPECT_EQ(1350u, params.quic_max_packet_length);
   EXPECT_EQ(1.0, params.alternative_service_probability_threshold);
@@ -239,6 +240,16 @@ TEST_F(IOThreadTest, EnableQuicFromFieldTrialGroup) {
   EXPECT_TRUE(params.quic_host_whitelist.empty());
 }
 
+TEST_F(IOThreadTest,
+       DisableQuicWhenConnectionTimesOutWithOpenStreamsFromFieldTrialParams) {
+  field_trial_group_ = "Enabled";
+  field_trial_params_["disable_quic_on_timeout_with_open_streams"] = "true";
+  ConfigureQuicGlobals();
+  net::HttpNetworkSession::Params params;
+  InitializeNetworkSessionParams(&params);
+  EXPECT_TRUE(params.disable_quic_on_timeout_with_open_streams);
+}
+
 TEST_F(IOThreadTest, EnableQuicFromQuicProxyFieldTrialGroup) {
   const struct {
     std::string field_trial_group_name;

net/http/http_network_session.cc

@@ -101,6 +101,7 @@ HttpNetworkSession::Params::Params()
       enable_npn(true),
       enable_brotli(false),
       enable_quic(false),
+      disable_quic_on_timeout_with_open_streams(false),
       enable_quic_for_proxies(false),
       enable_quic_port_selection(true),
       quic_always_require_handshake_confirmation(false),

net/http/http_network_session.h

@@ -121,6 +121,8 @@ class NET_EXPORT HttpNetworkSession
 
     // Enables QUIC support.
     bool enable_quic;
+    // Disable QUIC if a connection times out with open streams.
+    bool disable_quic_on_timeout_with_open_streams;
     // Enables QUIC for proxies.
     bool enable_quic_for_proxies;
     // Instruct QUIC to use consistent ephemeral ports when talking to