Update Context Client Visibility to use Scoped Pattern

gpu/command_buffer/client/scoped_visibility_impl.cc

Index: gpu/command_buffer/client/scoped_visibility_impl.cc
diff --git a/gpu/command_buffer/client/scoped_visibility_impl.cc b/gpu/command_buffer/client/scoped_visibility_impl.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a5f0949d998bb3518a90658a9f051f93e9030f47
--- /dev/null
+++ b/gpu/command_buffer/client/scoped_visibility_impl.cc
@@ -0,0 +1,24 @@
+// 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.
+
+#include "gpu/command_buffer/client/scoped_visibility_impl.h"
+
+#include "base/logging.h"
+
+namespace gpu {
+
+ScopedVisibilityImpl::ScopedVisibilityImpl(ContextSupport* context_support)
+    : initial_context_support_(context_support), released_(false) {}
+
+ScopedVisibilityImpl::~ScopedVisibilityImpl() {
+  DCHECK(released_);
+}
+
+void ScopedVisibilityImpl::Release(ContextSupport* context_support) {
+  DCHECK(!released_);
+  DCHECK_EQ(initial_context_support_, context_support);
+  released_ = true;
+}
+
+}  // namespace gpu