media: Add Feature to control External Clear Key key system support

media/base/media_switches.cc

 // Copyright (c) 2012 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 "build/build_config.h"
 #include "media/base/media_switches.h"
 
 namespace switches {
 
 // Allow users to specify a custom buffer size for debugging purpose.
@@ skipping 149 matching lines @@
       base::FEATURE_ENABLED_BY_DEFAULT
 };
 #else
       base::FEATURE_DISABLED_BY_DEFAULT
 };
 #endif
 
 // Use shared block-based buffering for media.
 const base::Feature kUseNewMediaCache{"use-new-media-cache",
                                       base::FEATURE_ENABLED_BY_DEFAULT};
+
 // Correct video colors based on output display?
 const base::Feature kVideoColorManagement{"video-color-management",
                                           base::FEATURE_DISABLED_BY_DEFAULT};
 
+// Enables support for External Clear Key (ECK) key system for testing on
+// supported platforms. On platforms that do not support ECK, this feature has
+// no effect.
+const base::Feature kExternalClearKeyForTesting{
+    "external-clear-key-for-testing", base::FEATURE_DISABLED_BY_DEFAULT};
+
 }  // namespace media