Move RegisterContentSchemes from public url_constants into non-public url_schemes.

content/common/url_schemes.h

+// Copyright (c) 2012 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 CONTENT_COMMON_URL_SCHEMES_H_
+#define CONTENT_COMMON_URL_SCHEMES_H_
+#pragma once
+
+#include "content/common/content_export.h"
+
+namespace content {
+
+// Note: ContentMainRunner calls this method internally as part of main
+// initialziation, so this function generally should not be called by
+// embedders. It's exported to facilitate test harnesses that do not
+// utilize ContentMainRunner and that do not wish to lock the set
+// of standard schemes at init time.
+//
+// Called near the beginning of startup to register URL schemes that should
+// be parsed as "standard" with the googleurl library. Optionally, the set
+// of standard schemes is locked down. The embedder can add additional
+// schemes by overriding the ContentClient::AddAdditionalSchemes method.
+CONTENT_EXPORT void RegisterContentSchemes(bool lock_standard_schemes);
+
+}  // namespace content
+
+#endif  // CONTENT_COMMON_URL_SCHEMES_H_