Log to UMA when x-origin frames (1) are created and (2) become visible

third_party/WebKit/Source/core/frame/LocalFrame.h

Index: third_party/WebKit/Source/core/frame/LocalFrame.h
diff --git a/third_party/WebKit/Source/core/frame/LocalFrame.h b/third_party/WebKit/Source/core/frame/LocalFrame.h
index 5e228406b11da8c7808cbb18dc89cb51f394f045..7a743a84cecdf28e15b44bc1ead96d7077f13fc8 100644
--- a/third_party/WebKit/Source/core/frame/LocalFrame.h
+++ b/third_party/WebKit/Source/core/frame/LocalFrame.h
@@ -185,6 +185,8 @@ public:
 
     PluginData* pluginData() const;
 
+    void onVisibilityMaybeChanged(bool visible);
+
 private:
     friend class FrameNavigationDisabler;
 
@@ -227,6 +229,9 @@ private:
     Member<InstrumentingAgents> m_instrumentingAgents;
 
     ServiceRegistry* const m_serviceRegistry;
+
+    bool m_visibilityWasLogged;
+    bool m_creationWasLogged;
 };
 
 inline void LocalFrame::init()