Add MediaKeys::GetCdmId().

media/base/media_keys.h

Index: media/base/media_keys.h
diff --git a/media/base/media_keys.h b/media/base/media_keys.h
index ac4f8a4a24f8735d68030543987331154b8a98e4..022f6bcce29078d5ab3142dc0eaa9074b900906a 100644
--- a/media/base/media_keys.h
+++ b/media/base/media_keys.h
@@ -71,7 +71,10 @@ class MEDIA_EXPORT MediaKeys {
     PERSISTENT_SESSION
   };
 
-  const static uint32 kInvalidSessionId = 0;
+  static const uint32 kInvalidSessionId = 0;
+#if defined(ENABLE_BROWSER_CDMS)
+  static const int kInvalidCdmId = 0;
+#endif
 
   MediaKeys();
   virtual ~MediaKeys();
@@ -123,6 +126,12 @@ class MEDIA_EXPORT MediaKeys {
   // to be valid during the MediaKeys' lifetime.
   virtual Decryptor* GetDecryptor();
 
+#if defined(ENABLE_BROWSER_CDMS)
+  // Returns the CDM ID associated with |this|. May be kInvalidCdmId if no CDM
+  // ID is associated.
+  virtual int GetCdmId() const = 0;
+#endif
+
  private:
   DISALLOW_COPY_AND_ASSIGN(MediaKeys);
 };