Add flag to override Effective Connection Type

chrome/browser/about_flags.cc

Index: chrome/browser/about_flags.cc
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index d9a048eea033df659f8cee2ab3ce9477fec9a181..f27782ff07edd9a09c28a82a28f1e54bc1bf10d1 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -85,6 +85,7 @@
 #include "media/media_features.h"
 #include "media/midi/midi_switches.h"
 #include "net/cert/cert_verify_proc_android.h"
+#include "net/nqe/effective_connection_type.h"
 #include "ppapi/features/features.h"
 #include "printing/features/features.h"
 #include "services/device/public/cpp/device_features.h"
@@ -721,6 +722,33 @@ const FeatureEntry::Choice kAutoplayPolicyChoices[] = {
 #endif
 };
 
+const FeatureEntry::Choice kForceEffectiveConnectionTypeChoices[] = {
+    {flags_ui::kGenericExperimentChoiceDefault, "", ""},
+    {flag_descriptions::kEffectiveConnectionTypeUnknownDescription,
+     switches::kForceEffectiveConnectionType,
+     net::kEffectiveConnectionTypeUnknown},
+    {flag_descriptions::kEffectiveConnectionTypeOfflineDescription,
+     switches::kForceEffectiveConnectionType,
+     net::kEffectiveConnectionTypeOffline},
+    {flag_descriptions::kEffectiveConnectionTypeSlow2GDescription,
+     switches::kForceEffectiveConnectionType,
+     net::kEffectiveConnectionTypeSlow2G},
+    {flag_descriptions::kEffectiveConnectionType2GDescription,
+     switches::kForceEffectiveConnectionType, net::kEffectiveConnectionType2G},
+    {flag_descriptions::kEffectiveConnectionType3GDescription,
+     switches::kForceEffectiveConnectionType, net::kEffectiveConnectionType3G},
+    {flag_descriptions::kEffectiveConnectionType4GDescription,
+     switches::kForceEffectiveConnectionType, net::kEffectiveConnectionType4G},
+};
+
+// Ensure that all effective connection types returned by Network Quality

[RyanSturm, 2017/05/01 23:08:34]

Maybe add a static_assert to make sure kForceEffectiveConnectionTypeChoices has
length net::EFFECTIVE_CONNECTION_TYPE_LAST

[tbansal1, 2017/05/02 00:01:50]

Done.

+// Estimator (NQE) are also exposed via flags.
+static_assert(net::EFFECTIVE_CONNECTION_TYPE_UNKNOWN == 0,
+              "ECT enum value is not handled.");
+static_assert(net::EFFECTIVE_CONNECTION_TYPE_4G + 1 ==
+                  net::EFFECTIVE_CONNECTION_TYPE_LAST,
+              "ECT enum value is not handled.");
+
 const FeatureEntry::FeatureParam kNoStatePrefetchEnabled[] = {
     {prerender::kNoStatePrefetchFeatureModeParameterName,
      prerender::kNoStatePrefetchFeatureModeParameterPrefetch}};
@@ -2765,6 +2793,11 @@ const FeatureEntry kFeatureEntries[] = {
      flag_descriptions::kAutoplayPolicyDescription, kOsAll,
      MULTI_VALUE_TYPE(kAutoplayPolicyChoices)},
 
+    {"force-effective-connection-type",
+     flag_descriptions::kForceEffectiveConnectionTypeName,
+     flag_descriptions::kForceEffectiveConnectionTypeDescription, kOsAll,
+     MULTI_VALUE_TYPE(kForceEffectiveConnectionTypeChoices)},
+
     // NOTE: Adding new command-line switches requires adding corresponding
     // entries to enum "LoginCustomFlags" in histograms.xml. See note in
     // histograms.xml and don't forget to run AboutFlagsHistogramTest unit test.