Add allocator interface for use by cdm_adapter

media/cdm/cdm_buffer_allocator.cc

Index: media/cdm/cdm_buffer_allocator.cc
diff --git a/media/cdm/cdm_buffer_allocator.cc b/media/cdm/cdm_buffer_allocator.cc
new file mode 100644
index 0000000000000000000000000000000000000000..2b55ea83d3cfeb59a14671853f4fcdc191d160f2
--- /dev/null
+++ b/media/cdm/cdm_buffer_allocator.cc
@@ -0,0 +1,13 @@
+// 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 "media/cdm/cdm_buffer_allocator.h"
+
+namespace media {
+
+CdmBufferAllocator::CdmBufferAllocator() {}
+
+CdmBufferAllocator::~CdmBufferAllocator() {}
+
+}  // namespace media