Implement the events for Background Fetch

third_party/WebKit/Source/modules/background_fetch/BackgroundFetchEvent.h

Index: third_party/WebKit/Source/modules/background_fetch/BackgroundFetchEvent.h
diff --git a/third_party/WebKit/Source/modules/background_fetch/BackgroundFetchEvent.h b/third_party/WebKit/Source/modules/background_fetch/BackgroundFetchEvent.h
new file mode 100644
index 0000000000000000000000000000000000000000..d50fe4deec45853292ff9220dde5279f63efb4a3
--- /dev/null
+++ b/third_party/WebKit/Source/modules/background_fetch/BackgroundFetchEvent.h
@@ -0,0 +1,43 @@
+// Copyright 2017 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 BackgroundFetchEvent_h
+#define BackgroundFetchEvent_h
+
+#include "modules/serviceworkers/ExtendableEvent.h"
+#include "platform/heap/Handle.h"
+#include "wtf/text/AtomicString.h"
+
+namespace blink {
+
+class BackgroundFetchEventInit;
+
+class BackgroundFetchEvent : public ExtendableEvent {
+  DEFINE_WRAPPERTYPEINFO();
+
+ public:
+  static BackgroundFetchEvent* create(
+      const AtomicString& type,
+      const BackgroundFetchEventInit& initializer) {
+    return new BackgroundFetchEvent(type, initializer);
+  }
+
+  ~BackgroundFetchEvent() override;
+
+  // Web Exposed attribute defined in the IDL file.
+  String tag() const;
+
+  // ExtendableEvent interface.
+  const AtomicString& interfaceName() const override;
+
+ protected:
+  BackgroundFetchEvent(const AtomicString& type,
+                       const BackgroundFetchEventInit&);
+
+  String m_tag;
+};
+
+}  // namespace blink
+
+#endif  // BackgroundFetchEvent_h