Add an IPC to return the platform supported key-system names in Android.

components/cdm/renderer/android_key_systems.h

+// Copyright 2014 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 COMPONENTS_CDM_RENDERER_ANDROID_KEY_SYSTEMS_H_
+#define COMPONENTS_CDM_RENDERER_ANDROID_KEY_SYSTEMS_H_
+
+#include <vector>
+
+#include "content/public/renderer/key_system_info.h"
+
+namespace cdm {
+
+void AddAndroidWidevine(
+    std::vector<content::KeySystemInfo>* concrete_key_systems);
+
+// Add platform-supported key systems which are not explicitly handled
+// by Chrome.
+void AddAndroidPlatformKeySystems(
+    std::vector<content::KeySystemInfo>* concrete_key_systems);
+
+}  // namespace cdm
+
+#endif  // COMPONENTS_CDM_RENDERER_ANDROID_KEY_SYSTEMS_H_