Index: third_party/WebKit/Source/core/dom/ElementVisibilityObserver.h |
diff --git a/third_party/WebKit/Source/core/dom/ElementVisibilityObserver.h b/third_party/WebKit/Source/core/dom/ElementVisibilityObserver.h |
index 9e0b69c483cdbee94d7b40a13d37e5d5de95ee8f..ef982b86225a44b8e8c7a90d1d210dbcbdce7805 100644 |
--- a/third_party/WebKit/Source/core/dom/ElementVisibilityObserver.h |
+++ b/third_party/WebKit/Source/core/dom/ElementVisibilityObserver.h |
@@ -33,7 +33,8 @@ class CORE_EXPORT ElementVisibilityObserver final |
ElementVisibilityObserver(Element*, std::unique_ptr<VisibilityCallback>); |
virtual ~ElementVisibilityObserver(); |
- void Start(); |
+ // The |threshold| is the minimum fraction that needs to be visible. |
+ void Start(float threshold = 0.0); |
void Stop(); |
void DeliverObservationsForTesting(); |