Include viewport visibility checks for autoplay experiment.

third_party/WebKit/Source/core/layout/LayoutMedia.h

Index: third_party/WebKit/Source/core/layout/LayoutMedia.h
diff --git a/third_party/WebKit/Source/core/layout/LayoutMedia.h b/third_party/WebKit/Source/core/layout/LayoutMedia.h
index 819cf2fa6ff5c6af53cba3b3a8630aedafdec162..5f0c7ca0315a897694957202a32c2df7d723f7fa 100644
--- a/third_party/WebKit/Source/core/layout/LayoutMedia.h
+++ b/third_party/WebKit/Source/core/layout/LayoutMedia.h
@@ -51,7 +51,20 @@ public:
 
     const char* name() const override { return "LayoutMedia"; }
 
+    // Temporary callback for crbug.com/587345,402044
+    void notifyPositionMayHaveChanged(const IntRect&);
+
+    // Change whether we want or don't want to receive position change
+    // notifications.  This will cause us to start / stop receiving change
+    // notifications if possible.
+    // Temporary method for crbug.com/587345,402044
+    void setRequestPositionUpdates(bool);
+
 protected:
+    // Temporary overrides for crbug.com/587345,402044
+    void willBeDestroyed() override;
+    void insertedIntoTree() override;
+
     void layout() override;
 
     bool isOfType(LayoutObjectType type) const override { return type == LayoutObjectMedia || LayoutImage::isOfType(type); }