--- a/dom/media/gmp/moz.build
+++ b/dom/media/gmp/moz.build
@@ -63,16 +63,17 @@ EXPORTS += [
     'GMPVideoEncoderChild.h',
     'GMPVideoEncoderParent.h',
     'GMPVideoEncoderProxy.h',
     'GMPVideoHost.h',
     'GMPVideoi420FrameImpl.h',
     'GMPVideoPlaneImpl.h',
     'widevine-adapter/content_decryption_module.h',
     'widevine-adapter/content_decryption_module_export.h',
+    'widevine-adapter/content_decryption_module_ext.h',
 ]
 
 UNIFIED_SOURCES += [
     'ChromiumCDMAdapter.cpp',
     'ChromiumCDMChild.cpp',
     'ChromiumCDMParent.cpp',
     'ChromiumCDMProxy.cpp',
     'DecryptJob.cpp',

new file mode 100644
--- /dev/null
+++ b/dom/media/gmp/widevine-adapter/content_decryption_module_ext.h
@@ -0,0 +1,64 @@
+// Copyright 2017 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 CDM_CONTENT_DECRYPTION_MODULE_EXT_H_
+#define CDM_CONTENT_DECRYPTION_MODULE_EXT_H_
+
+#if defined(_WIN32)
+#include <windows.h>
+#endif
+
+#include "content_decryption_module_export.h"
+
+#if defined(_MSC_VER)
+typedef unsigned int uint32_t;
+#else
+#include <stdint.h>
+#endif
+
+namespace cdm {
+
+#if defined(_WIN32)
+typedef wchar_t FilePathCharType;
+typedef HANDLE PlatformFile;
+const PlatformFile kInvalidPlatformFile = INVALID_HANDLE_VALUE;
+#else
+typedef char FilePathCharType;
+typedef int PlatformFile;
+const PlatformFile kInvalidPlatformFile = -1;
+#endif  // defined(_WIN32)
+
+struct HostFile {
+  HostFile(const FilePathCharType* file_path,
+           PlatformFile file,
+           PlatformFile sig_file)
+      : file_path(file_path), file(file), sig_file(sig_file) {}
+
+  // File that is part of the host of the CDM.
+  const FilePathCharType* file_path = nullptr;
+  PlatformFile file = kInvalidPlatformFile;
+
+  // Signature file for |file|.
+  PlatformFile sig_file = kInvalidPlatformFile;
+};
+
+}  // namespace cdm
+
+extern "C" {
+
+// Functions in this file are dynamically retrieved by their versioned function
+// names. Increment the version number for any backward incompatible API
+// changes.
+
+// Verifies CDM host. All files in |host_files| are opened in read-only mode.
+//
+// Returns false and closes all files if there is an immediate failure.
+// Otherwise returns true as soon as possible and processes the files
+// asynchronously. All files MUST be closed by the CDM after this one-time
+// processing is finished.
+CDM_API bool VerifyCdmHost_0(const cdm::HostFile* host_files,
+                             uint32_t num_files);
+}
+
+#endif  // CDM_CONTENT_DECRYPTION_MODULE_EXT_H_