Declarative resource hints go through mojo IPC to //content

third_party/WebKit/Source/platform/PlatformMojoServices.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 PlatformMojoServices_h
+#define PlatformMojoServices_h
+
+#include "public/platform/resource_hints.mojom-blink.h"
+
+namespace blink {
+
+class PlatformMojoServices {
+public:
+    PlatformMojoServices();
+
+    const mojom::blink::ResourceHintsHandlerPtr& resourceHintsHandler();
+
+private:
+    mojom::blink::ResourceHintsHandlerPtr m_resourceHintsHandler;
+};
+
+} // namespace blink
+
+#endif // PlatformMojoServices_h