Update Context Client Visibility to use Scoped Pattern

gpu/command_buffer/client/scoped_visibility_impl.h

+// 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 GPU_COMMAND_BUFFER_CLIENT_SCOPED_VISIBILITY_IMPL_H_
+#define GPU_COMMAND_BUFFER_CLIENT_SCOPED_VISIBILITY_IMPL_H_
+
+#include <memory>
+
+#include "gpu/command_buffer/client/context_support.h"
+#include "gpu/gpu_export.h"
+
+namespace gpu {
+
+class GPU_EXPORT ScopedVisibilityImpl
+    : public ContextSupport::ScopedVisibility {
+ public:
+  explicit ScopedVisibilityImpl(ContextSupport* context_support);
+  ~ScopedVisibilityImpl();
+  void Release(ContextSupport* context_support);
+
+ private:
+  // |initial_context_support_| is just stored/used for sanity-checking Release.
+  const ContextSupport* const initial_context_support_;
+  bool released_;
+};
+
+}  // namespace gpu
+
+#endif  // GPU_COMMAND_BUFFER_CLIENT_SCOPED_VISIBILITY_IMPL_H_