media: CdmFactory creates CDM (MediaKeys) asynchronously.

media/blink/webcontentdecryptionmodule_impl.h

 // Copyright 2013 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 MEDIA_BLINK_WEBCONTENTDECRYPTIONMODULE_IMPL_H_
 #define MEDIA_BLINK_WEBCONTENTDECRYPTIONMODULE_IMPL_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/string16.h"
@@ skipping 34 matching lines @@
       const uint8* server_certificate,
       size_t server_certificate_length,
       blink::WebContentDecryptionModuleResult result);
 
   // Returns the CdmContext associated with this CDM, which must not be nullptr.
   // TODO(jrummell): Figure out lifetimes, as WMPI may still use the decryptor
   // after WebContentDecryptionModule is freed. http://crbug.com/330324
   CdmContext* GetCdmContext();
 
  private:
+  friend CdmSessionAdapter;
+
   // Takes reference to |adapter|.
   WebContentDecryptionModuleImpl(scoped_refptr<CdmSessionAdapter> adapter);
 
   scoped_refptr<CdmSessionAdapter> adapter_;
 
   DISALLOW_COPY_AND_ASSIGN(WebContentDecryptionModuleImpl);
 };
 
 // Allow typecasting from blink type as this is the only implementation.
 inline WebContentDecryptionModuleImpl* ToWebContentDecryptionModuleImpl(
     blink::WebContentDecryptionModule* cdm) {
   return static_cast<WebContentDecryptionModuleImpl*>(cdm);
 }
 
 }  // namespace media
 
 #endif  // MEDIA_BLINK_WEBCONTENTDECRYPTIONMODULE_IMPL_H_