Bind Window focus ability to the ExecutionContext instead of the process.

Source/core/dom/ScopedWindowFocusAllowedIndicator.h

+// 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