Reland of NaCl cleanup: Split out irt_interfaces.cc from irt_ppapi.cc

ppapi/nacl_irt/irt_interfaces.h

Index: ppapi/nacl_irt/irt_interfaces.h
diff --git a/ppapi/nacl_irt/irt_interfaces.h b/ppapi/nacl_irt/irt_interfaces.h
new file mode 100644
index 0000000000000000000000000000000000000000..0971900d8316a61bbb4e17da84e70f9f13900e4f
--- /dev/null
+++ b/ppapi/nacl_irt/irt_interfaces.h
@@ -0,0 +1,15 @@
+// Copyright 2015 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 PPAPI_NACL_IRT_IRT_INTERFACES_H_
+#define PPAPI_NACL_IRT_IRT_INTERFACES_H_
+
+#include <stdlib.h>
+
+extern const struct nacl_irt_ppapihook nacl_irt_ppapihook;
+
+size_t chrome_irt_query(const char* interface_ident,
+                        void* table, size_t tablesize);
+
+#endif  // PPAPI_NACL_IRT_IRT_INTERFACES_H_