Allow for pausing background tabs on desktop via about:flags.

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 495a80a66b444b4796c3958ec8e4e6af84523c1b..3fa3fb26e34e2414abeb38c60f43ba05f0a0b6ec 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -36,6 +36,7 @@
 #include "chrome/common/chrome_features.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/features.h"
+#include "chrome/common/pause_tabs_field_trial.h"
 #include "chrome/grit/chromium_strings.h"
 #include "components/autofill/core/browser/autofill_experiments.h"
 #include "components/autofill/core/common/autofill_switches.h"
@@ -710,6 +711,38 @@ const FeatureEntry::FeatureVariation
         {"Learning", kSpeculativeResourcePrefetchingLearning,
          arraysize(kSpeculativeResourcePrefetchingLearning), nullptr}};
 
+const FeatureEntry::FeatureParam kPauseBackgroundTabsMinimalEngagment[] = {
+    {pausetabs::kPauseBackgroundTabsFeatureParameterName,
+     pausetabs::kPauseBackgroundTabsFeatureModeParameterMinimal}};
+
+const FeatureEntry::FeatureParam kPauseBackgroundTabsLowEngagment[] = {
+    {pausetabs::kPauseBackgroundTabsFeatureParameterName,
+     pausetabs::kPauseBackgroundTabsFeatureModeParameterLow}};
+
+const FeatureEntry::FeatureParam kPauseBackgroundTabsMediumEngagment[] = {
+    {pausetabs::kPauseBackgroundTabsFeatureParameterName,
+     pausetabs::kPauseBackgroundTabsFeatureModeParameterMedium}};
+
+const FeatureEntry::FeatureParam kPauseBackgroundTabsHighEngagment[] = {
+    {pausetabs::kPauseBackgroundTabsFeatureParameterName,
+     pausetabs::kPauseBackgroundTabsFeatureModeParameterHigh}};
+
+const FeatureEntry::FeatureParam kPauseBackgroundTabsMaxEngagment[] = {
+    {pausetabs::kPauseBackgroundTabsFeatureParameterName,
+     pausetabs::kPauseBackgroundTabsFeatureModeParameterMax}};
+
+const FeatureEntry::FeatureVariation kPauseBackgroundTabsVariations[] = {
+    {"minimal engagement", kPauseBackgroundTabsMinimalEngagment,
+     arraysize(kPauseBackgroundTabsMinimalEngagment), nullptr},
+    {"low engagement", kPauseBackgroundTabsLowEngagment,
+     arraysize(kPauseBackgroundTabsLowEngagment), nullptr},
+    {"medium engagement", kPauseBackgroundTabsMediumEngagment,
+     arraysize(kPauseBackgroundTabsMediumEngagment), nullptr},
+    {"high engagement", kPauseBackgroundTabsHighEngagment,
+     arraysize(kPauseBackgroundTabsHighEngagment), nullptr},
+    {"max engagement", kPauseBackgroundTabsMaxEngagment,
+     arraysize(kPauseBackgroundTabsMaxEngagment), nullptr}};
+
 #if defined(OS_ANDROID)
 const FeatureEntry::FeatureParam
 kAutofillCreditCardPopupLayoutFeatureVariationIconAtStart[] = {
@@ -2572,6 +2605,15 @@ const FeatureEntry kFeatureEntries[] = {
      FEATURE_VALUE_TYPE(chrome::android::kCustomContextMenu)},
 #endif  // OS_ANDROID
 
+#if defined(OS_CHROMEOS) || defined(OS_LINUX) || defined(OS_MACOSX) || \
+    defined(OS_WIN)
+    {"pause-background-tabs", flag_descriptions::kPauseBackgroundTabsName,
+     flag_descriptions::kPauseBackgroundTabsDescription, kOsDesktop,
+     FEATURE_WITH_PARAMS_VALUE_TYPE(pausetabs::kPauseBackgroundTabsFeature,
+                                    kPauseBackgroundTabsVariations,
+                                    "PauseBackgroundTabs")},
+#endif
+
     // 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.