Initial ResizeObserver implementation

third_party/WebKit/Source/core/observer/ResizeObserverCallback.h

Index: third_party/WebKit/Source/core/observer/ResizeObserverCallback.h
diff --git a/third_party/WebKit/Source/core/observer/ResizeObserverCallback.h b/third_party/WebKit/Source/core/observer/ResizeObserverCallback.h
new file mode 100644
index 0000000000000000000000000000000000000000..6cffeb849b1fc4d956c825c6cce9fe94116f99d0
--- /dev/null
+++ b/third_party/WebKit/Source/core/observer/ResizeObserverCallback.h
@@ -0,0 +1,25 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef ResizeObserverCallback_h
+#define ResizeObserverCallback_h
+
+#include "platform/heap/Handle.h"
+
+namespace blink {
+
+class ExecutionContext;
+class ResizeObserver;
+class ResizeObserverEntry;
+
+class ResizeObserverCallback : public GarbageCollectedFinalized<ResizeObserverCallback> {
+public:
+    virtual ~ResizeObserverCallback() {}
+    virtual void handleEvent(const HeapVector<Member<ResizeObserverEntry>>& entries, ResizeObserver*) = 0;
+    DEFINE_INLINE_VIRTUAL_TRACE() { }
+};
+
+} // namespace blink
+
+#endif // ResizeObserverCallback_h