media: Add experimental feature to enable Mojo CDM on desktop Chromium

media/cdm/cdm_allocator.h

Index: media/cdm/cdm_allocator.h
diff --git a/media/cdm/cdm_allocator.h b/media/cdm/cdm_allocator.h
index b06baac14ca2e7edd4be2671b03debcfa9c18b05..a15b92f14e177b2875689df37de113e413d7a65f 100644
--- a/media/cdm/cdm_allocator.h
+++ b/media/cdm/cdm_allocator.h
@@ -10,6 +10,7 @@
 
 #include <memory>
 
+#include "base/callback.h"
 #include "base/macros.h"
 #include "media/base/media_export.h"
 
@@ -23,6 +24,9 @@ class VideoFrameImpl;
 
 class MEDIA_EXPORT CdmAllocator {
  public:
+  // Callback to create CdmAllocator for the created CDM.
+  using CreationCB = base::RepeatingCallback<std::unique_ptr<CdmAllocator>()>;
+
   virtual ~CdmAllocator();
 
   // Creates a buffer with at least |capacity| bytes. Caller is required to