Use FrameIsAd to decide whether to isolate a frame in TopDocumentIsolation mode.

content/public/common/content_features.h

Index: content/public/common/content_features.h
diff --git a/content/public/common/content_features.h b/content/public/common/content_features.h
index 1c49647ef0df780d8a078a6923448ce78e7ffe8b..ab6e8a0dee9a96c9deb6f93d5c42b37ed0c30d2d 100644
--- a/content/public/common/content_features.h
+++ b/content/public/common/content_features.h
@@ -75,7 +75,41 @@ CONTENT_EXPORT extern const base::Feature kSkipCompositingSmallScrollers;
 CONTENT_EXPORT extern const base::Feature kSlimmingPaintInvalidation;
 CONTENT_EXPORT extern const base::Feature kTimerThrottlingForHiddenFrames;
 CONTENT_EXPORT extern const base::Feature kTokenBinding;
+
 CONTENT_EXPORT extern const base::Feature kTopDocumentIsolation;
+
+// If the kTopDocumentIsolation base::Feature is enabled, then it can be
+// configured by additional parameters (see also GetFieldTrialParamsByFeature).
+// |kTopDocumentIsolationModeParam| is the name of an optional parameter that
+// specifies TopDocumentIsolationMode.  Valid values of this parameter are
+// strings that represent numeric values of TopDocumentIsolationMode enum values
+// (e.g. "1" for TopDocumentIsolationMode::CrossSite).
+CONTENT_EXPORT extern const char kTopDocumentIsolationModeParam[];
+
+// If the kTopDocumentIsolation base::Feature is enabled, the values of this
+// enum represent the mode for selecting *which* frames to isolate.
+//
+// These values should NOT be renumbered, because 1) they can be specified in a
+// server-side trial config and 2) they can be persisted in the state of
+// chrome://flags selected by the user.
+enum class TopDocumentIsolationMode {
+  // This value indicates that kTopDocumentIsolationModeParam was not specified.
+  // Corresponds to "Enabled" state in chrome://flags (i.e. the user didn't
+  // select a more specific isolation mode).
+  Unspecified = 0,
+
+// Each of the modes below corresponds to "Enabled (<name> - <description>)"
+// state in chrome://flags.
+#define FOR_EACH_TDI_MODE(V)                                        \
+  V(CrossSite, 1,                                                   \
+    "isolate all frames from sites other than the top-level frame") \
+  V(Ads, 2, "isolate only cross-site ads detected by heuristics")
+
+#define DEFINE_TDI_MODE_ENUM_VALUE(name, value, description) name = value,
+  FOR_EACH_TDI_MODE(DEFINE_TDI_MODE_ENUM_VALUE)
+#undef DEFINE_TDI_MODE_ENUM_VALUE
+};
+
 CONTENT_EXPORT extern const base::Feature kTouchpadAndWheelScrollLatching;
 CONTENT_EXPORT extern const base::Feature kUseFeaturePolicyForPermissions;
 CONTENT_EXPORT extern const base::Feature kUseMojoAudioOutputStreamFactory;