Revert 186849 "Bind Window focus ability to the ExecutionContext..."

Source/core/dom/ScopedWindowFocusAllowedIndicator.h

Index: Source/core/dom/ScopedWindowFocusAllowedIndicator.h
===================================================================
--- Source/core/dom/ScopedWindowFocusAllowedIndicator.h	(revision 187183)
+++ Source/core/dom/ScopedWindowFocusAllowedIndicator.h	(working copy)
@@ -1,24 +0,0 @@
-// Copyright 2014 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 ScopedWindowFocusAllowedIndicator_h
-#define ScopedWindowFocusAllowedIndicator_h
-
-#include "core/dom/ContextLifecycleObserver.h"
-#include "wtf/Noncopyable.h"
-
-namespace blink {
-
-class ExecutionContext;
-
-class ScopedWindowFocusAllowedIndicator : ContextLifecycleObserver {
-    WTF_MAKE_NONCOPYABLE(ScopedWindowFocusAllowedIndicator);
-public:
-    explicit ScopedWindowFocusAllowedIndicator(ExecutionContext*);
-    ~ScopedWindowFocusAllowedIndicator();
-};
-
-} // namespace blink
-
-#endif // ScopedWindowFocusAllowedIndicator_h