Add runtime setting to force passive event listeners.

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 923c1c346bf128d1342858bb0be45781fc6e08d0..8b11faf46c65de8c2a665a1728739da7be7adf31 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -185,6 +185,16 @@ const FeatureEntry::Choice kNaClDebugMaskChoices[] = {
 };
 #endif
 
+const FeatureEntry::Choice kPassiveListenersChoices[] = {
+    {IDS_GENERIC_EXPERIMENT_CHOICE_DEFAULT, "", ""},
+    {IDS_FLAGS_PASSIVE_EVENT_LISTENER_DOCUMENT_TRUE,
+     switches::kPassiveListenersDefault, "documentonlytrue"},
+    {IDS_FLAGS_PASSIVE_EVENT_LISTENER_TRUE, switches::kPassiveListenersDefault,
+     "true"},
+    {IDS_FLAGS_PASSIVE_EVENT_LISTENER_FORCE_ALL_TRUE,
+     switches::kPassiveListenersDefault, "forcealltrue"},
+};
+
 const FeatureEntry::Choice kMarkNonSecureAsChoices[] = {
     {IDS_GENERIC_EXPERIMENT_CHOICE_DEFAULT, "", ""},
     {IDS_MARK_NON_SECURE_AS_NEUTRAL, security_state::switches::kMarkNonSecureAs,
@@ -882,9 +892,8 @@ const FeatureEntry kFeatureEntries[] = {
         IDS_FLAGS_ASH_ENABLE_MIRRORED_SCREEN_DESCRIPTION, kOsCrOS,
         SINGLE_VALUE_TYPE(ash::switches::kAshEnableMirroredScreen),
     },
-    {
-        "ash-md", IDS_FLAGS_ASH_MD, IDS_FLAGS_ASH_MD_DESCRIPTION, kOsCrOS,
-        MULTI_VALUE_TYPE(kAshMaterialDesignChoices)},
+    {"ash-md", IDS_FLAGS_ASH_MD, IDS_FLAGS_ASH_MD_DESCRIPTION, kOsCrOS,
+     MULTI_VALUE_TYPE(kAshMaterialDesignChoices)},
     {
         "ash-stable-overview-order", IDS_FLAGS_ASH_STABLE_OVERVIEW_ORDER_NAME,
         IDS_FLAGS_ASH_STABLE_OVERVIEW_ORDER_DESCRIPTION, kOsCrOS,
@@ -1528,8 +1537,7 @@ const FeatureEntry kFeatureEntries[] = {
      SINGLE_VALUE_TYPE(switches::kEnableWebRtcDtls12)},
 #endif
 #if defined(ENABLE_WEBRTC)
-    {"enable-webrtc-ecdsa",
-     IDS_FLAGS_WEBRTC_ECDSA_NAME,
+    {"enable-webrtc-ecdsa", IDS_FLAGS_WEBRTC_ECDSA_NAME,
      IDS_FLAGS_WEBRTC_ECDSA_DESCRIPTION, kOsAll,
      FEATURE_VALUE_TYPE(features::kWebRtcEcdsaDefault)},
 #endif
@@ -1835,20 +1843,22 @@ const FeatureEntry kFeatureEntries[] = {
      SINGLE_VALUE_TYPE(switches::kEnableFullscreenTabDetaching)},
 #endif
 #if defined(OS_ANDROID)
-    {"media-style-notification",
-     IDS_FLAGS_MEDIA_STYLE_NOTIFICATION_NAME,
+    {"media-style-notification", IDS_FLAGS_MEDIA_STYLE_NOTIFICATION_NAME,
      IDS_FLAGS_MEDIA_STYLE_NOTIFICATION_DESCRIPTION, kOsAndroid,
      FEATURE_VALUE_TYPE(chrome::android::kMediaStyleNotification)},
-    {"important-sites-in-cbd",
-     IDS_FLAGS_IMPORTANT_SITES_IN_CBD_NAME,
+    {"important-sites-in-cbd", IDS_FLAGS_IMPORTANT_SITES_IN_CBD_NAME,
      IDS_FLAGS_IMPORTANT_SITES_IN_CBD_DESCRIPTION, kOsAndroid,
      FEATURE_VALUE_TYPE(chrome::android::kImportantSitesInCBD)},
 #endif
     {"enable-pointer-events",  // FLAGS:RECORD_UMA
-      IDS_FLAGS_EXPERIMENTAL_POINTER_EVENT_NAME,
-      IDS_FLAGS_EXPERIMENTAL_POINTER_EVENT_DESCRIPTION,
-      kOsAll,
-      FEATURE_VALUE_TYPE(features::kPointerEvents)},
+     IDS_FLAGS_EXPERIMENTAL_POINTER_EVENT_NAME,
+     IDS_FLAGS_EXPERIMENTAL_POINTER_EVENT_DESCRIPTION, kOsAll,
+     FEATURE_VALUE_TYPE(features::kPointerEvents)},
+    {"passive-listener-default",  // FLAGS:RECORD_UMA
+     IDS_FLAGS_PASSIVE_EVENT_LISTENER_DEFAULT_NAME,
+     IDS_FLAGS_PASSIVE_EVENT_LISTENER_DEFAULT_DESCRIPTION, kOsAll,
+     MULTI_VALUE_TYPE(kPassiveListenersChoices)},
+
     // 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.