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 04178037a82674bef80642d9afbc57903e7bbebe..89df2f9a9b7e8775a35fc0f358ec9b36345d7efb 100644
--- a/content/public/common/content_features.h
+++ b/content/public/common/content_features.h
@@ -72,7 +72,30 @@ 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;
+
+CONTENT_EXPORT extern const char kTopDocumentIsolationModeParam[];
+
+// If TopDocumentIsolation is enabled, the mode for selecting *which* frames to
+// isolate can be one of the enum values below.
+enum class TopDocumentIsolationMode {
+  // Corresponds to "Enabled" state in chrome://flags (i.e. the user didn't
+  // select a more specific isolation mode).
+  Default = 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 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
+};
+

[Łukasz Anforowicz, 2017/07/01 00:10:53]

Charlie - do you have any thoughts on the location of the declarations
(kTopDocumentIsolationModeParam const and TopDocumentIsolationMode enum) above? 
Are they okay here?  Would you move them to another header?

Some of my earlier thoughts are in
https://codereview.chromium.org/2946113002/diff/80001/content/public/common/c...

 CONTENT_EXPORT extern const base::Feature kTouchpadAndWheelScrollLatching;
 CONTENT_EXPORT extern const base::Feature kUseFeaturePolicyForPermissions;
 CONTENT_EXPORT extern const base::Feature kUseMojoAudioOutputStreamFactory;