Add -ifsameorigin to autoplay experiment.

third_party/WebKit/Source/core/html/AutoplayExperimentHelper.h

Index: third_party/WebKit/Source/core/html/AutoplayExperimentHelper.h
diff --git a/third_party/WebKit/Source/core/html/AutoplayExperimentHelper.h b/third_party/WebKit/Source/core/html/AutoplayExperimentHelper.h
index 6595de029456a634bddb6e137012abec839ea645..2287c1e5377bf5dc68e553b7c1551aca8b6a8957 100644
--- a/third_party/WebKit/Source/core/html/AutoplayExperimentHelper.h
+++ b/third_party/WebKit/Source/core/html/AutoplayExperimentHelper.h
@@ -123,6 +123,7 @@ public:
         virtual bool isLegacyViewportType() = 0;
         virtual PageVisibilityState pageVisibilityState() const = 0;
         virtual String autoplayExperimentMode() const = 0;
+        virtual LocalFrame* frame() const = 0;
 
         // LayoutObject
         virtual void setRequestPositionUpdates(bool) = 0;
@@ -183,9 +184,15 @@ public:
         // Restrict gestureless autoplay to sites which contain the
         // viewport tag.
         IfMobile      = 1 << 5,
+        // Restrict gestureless autoplay to sites which are from the same origin
+        // as the top-level frame.
+        IfSameOrigin  = 1 << 6,
+        // When combined with IfSameOrigin, allow muted to override the same
+        // origin check.  Else, this does nothing.
+        OrMuted       = 1 << 7,
         // If gestureless autoplay is allowed, then mute the media before
         // starting to play.
-        PlayMuted     = 1 << 6,
+        PlayMuted     = 1 << 8,
     };
 
     DEFINE_INLINE_TRACE() { visitor->trace(m_client); }
@@ -200,6 +207,10 @@ private:
     // Un-register for position updates, if we are currently registered.
     void unregisterForPositionUpdatesIfNeeded();
 
+    // Return true if and only if our media element is in the same origin as the
+    // top-level frame.
+    bool isSameOrigin() const;
+
     // Return true if any only if this player meets (most) of the eligibility
     // requirements for the experiment to override the need for a user
     // gesture.  This includes everything except the visibility test.