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 ffd283ce19a8d581c8ffb39e209bd0d97f09bcc4..02f45e606c5d72ab78ae99ad19a985ee3f613115 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"
@@ -714,6 +715,36 @@ const FeatureEntry::FeatureVariation
         {"Learning", kSpeculativeResourcePrefetchingLearning,
          arraysize(kSpeculativeResourcePrefetchingLearning), nullptr}};
 
+#if defined(OS_CHROMEOS) || defined(OS_LINUX) || defined(OS_MACOSX) || \
+    defined(OS_WIN)
+const FeatureEntry::FeatureParam kPauseBackgroundTabsMinimalEngagment[] = {
+    {pausetabs::kFeatureName, pausetabs::kModeParamMinimal}};
+
+const FeatureEntry::FeatureParam kPauseBackgroundTabsLowEngagment[] = {
+    {pausetabs::kFeatureName, pausetabs::kModeParamLow}};
+
+const FeatureEntry::FeatureParam kPauseBackgroundTabsMediumEngagment[] = {
+    {pausetabs::kFeatureName, pausetabs::kModeParamMedium}};
+
+const FeatureEntry::FeatureParam kPauseBackgroundTabsHighEngagment[] = {
+    {pausetabs::kFeatureName, pausetabs::kModeParamHigh}};
+
+const FeatureEntry::FeatureParam kPauseBackgroundTabsMaxEngagment[] = {
+    {pausetabs::kFeatureName, pausetabs::kModeParamMax}};
+
+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}};
+#endif
+
 #if defined(OS_ANDROID)
 const FeatureEntry::FeatureParam
 kAutofillCreditCardPopupLayoutFeatureVariationIconAtStart[] = {
@@ -2604,6 +2635,15 @@ 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)
+    {pausetabs::kFeatureName, flag_descriptions::kPauseBackgroundTabsName,
+     flag_descriptions::kPauseBackgroundTabsDescription, kOsDesktop,
+     FEATURE_WITH_PARAMS_VALUE_TYPE(pausetabs::kFeature,
+                                    kPauseBackgroundTabsVariations,
+                                    "PauseBackgroundTabs")},
+#endif
+
 #if defined(USE_ASH)
     {"ash-enable-smooth-screen-rotation",
      flag_descriptions::kAshEnableSmoothScreenRotationName,