Add -ifsameorigin to autoplay experiment.

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

Index: third_party/WebKit/Source/core/html/AutoplayExperimentHelper.cpp
diff --git a/third_party/WebKit/Source/core/html/AutoplayExperimentHelper.cpp b/third_party/WebKit/Source/core/html/AutoplayExperimentHelper.cpp
index bbfbbe36f2c0692d0d8d03247198e7fff8e36e28..836dcfd8bda86ad36c83d15020d5476f952acc9d 100644
--- a/third_party/WebKit/Source/core/html/AutoplayExperimentHelper.cpp
+++ b/third_party/WebKit/Source/core/html/AutoplayExperimentHelper.cpp
@@ -327,6 +327,14 @@ bool AutoplayExperimentHelper::isEligible() const
         && !client().isLegacyViewportType())
         return false;
 
+    // If we require same-origin, then check the origin.  If we additionally
+    // allow "or muted", then also allow autoplay in that case.
+    if (enabled(IfSameOrigin) && client().frame()
+        && client().frame()->isCrossOrigin()) {
+        if (!enabled(OrMuted) || !client().muted())
+            return false;
+    }
+
     // If we require muted media and this is muted, then it is eligible.
     if (enabled(IfMuted))
         return client().muted();
@@ -394,6 +402,10 @@ AutoplayExperimentHelper::Mode AutoplayExperimentHelper::fromString(const String
         value |= IfMuted;
     if (mode.contains("-ifmobile"))
         value |= IfMobile;
+    if (mode.contains("-ifsameorigin"))
+        value |= IfSameOrigin;
+    if (mode.contains("-ormuted"))
+        value |= OrMuted;
     if (mode.contains("-playmuted"))
         value |= PlayMuted;