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 890ee365413ab35a9c84b85443d6548aa9953af0..2cd461fcf7d9373f7c1507e0248cbdfc09ee1ff0 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;
@@ -181,10 +182,16 @@ public:
         IfMuted           = 1 << 5,
         // Restrict gestureless autoplay to sites which contain the
         // viewport tag.
-        IfMobile          = 1 << 6,
+        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 << 7,
+        PlayMuted         = 1 << 8,
     };
 
     DEFINE_INLINE_TRACE() { visitor->trace(m_client); }