Block framebusts without a user gesture

content/public/common/content_features.cc

Index: content/public/common/content_features.cc
diff --git a/content/public/common/content_features.cc b/content/public/common/content_features.cc
index 14bd9de4a2447463d70094bdccd31a3e7f0a86c8..e0737e73fcdef2a7693fbf1a77ee6e91b3173782 100644
--- a/content/public/common/content_features.cc
+++ b/content/public/common/content_features.cc
@@ -45,6 +45,13 @@ const base::Feature kFeaturePolicy{"FeaturePolicy",
 const base::Feature kFontCacheScaling{"FontCacheScaling",
                                       base::FEATURE_DISABLED_BY_DEFAULT};
 
+// Enables a security restriction on iframes navigating their top frame.
+// When enabled, the navigation will only be permitted if the iframe is
+// same-origin to the top frame, or if a user gesture is being processed.
+const base::Feature kFramebustingNeedsSameOriginOrUserGesture{
+    "FramebustingNeedsSameOriginOrUserGesture",
+    base::FEATURE_ENABLED_BY_DEFAULT};
+
 // Enables extended Gamepad API features like motion tracking and haptics.
 const base::Feature kGamepadExtensions{"GamepadExtensions",
                                        base::FEATURE_DISABLED_BY_DEFAULT};