media: Support creation and SetCdm() for mojo based CDM.

media/mojo/services/mojo_cdm.h

Index: media/mojo/services/mojo_cdm.h
diff --git a/media/mojo/services/mojo_cdm.h b/media/mojo/services/mojo_cdm.h
index 68667dab6ccfa3b4c1150c98e972e4667d176431..8ffc0eff0a55823f5c9dc161707af9f9312da937 100644
--- a/media/mojo/services/mojo_cdm.h
+++ b/media/mojo/services/mojo_cdm.h
@@ -9,6 +9,7 @@
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
+#include "media/base/cdm_context.h"
 #include "media/base/media_keys.h"
 #include "media/mojo/interfaces/content_decryption_module.mojom.h"
 #include "media/mojo/services/mojo_type_trait.h"
@@ -22,11 +23,14 @@ namespace media {
 // A MediaKeys that proxies to a mojo::ContentDecryptionModule. That
 // mojo::ContentDecryptionModule proxies back to the MojoCdm via the
 // mojo::ContentDecryptionModuleClient interface.
-class MojoCdm : public MediaKeys, public mojo::ContentDecryptionModuleClient {
+class MojoCdm : public MediaKeys,
+                public CdmContext,
+                public mojo::ContentDecryptionModuleClient {
  public:
   // |media_renderer_provider| is a ServiceProvider from a connected
   //     Application that is hosting a mojo::MediaRenderer.
   MojoCdm(mojo::ContentDecryptionModulePtr remote_cdm,
+          int32_t cdm_id,
           const SessionMessageCB& session_message_cb,
           const SessionClosedCB& session_closed_cb,
           const LegacySessionErrorCB& legacy_session_error_cb,
@@ -54,6 +58,10 @@ class MojoCdm : public MediaKeys, public mojo::ContentDecryptionModuleClient {
                      scoped_ptr<SimpleCdmPromise> promise) final;
   CdmContext* GetCdmContext() final;
 
+  // CdmContext implementation.
+  media::Decryptor* GetDecryptor() final;
+  int GetCdmId() const final;
+
  private:
   // mojo::ContentDecryptionModuleClient implementation.
   void OnSessionMessage(const mojo::String& session_id,
@@ -89,6 +97,8 @@ class MojoCdm : public MediaKeys, public mojo::ContentDecryptionModuleClient {
   mojo::ContentDecryptionModulePtr remote_cdm_;
   mojo::Binding<ContentDecryptionModuleClient> binding_;
 
+  const int32_t cdm_id_;
+
   // Callbacks for firing session events.
   SessionMessageCB session_message_cb_;
   SessionClosedCB session_closed_cb_;