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..89204b75234fed942710e8566a1fc94c513a2858 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.
+  int GetCdmId() const;

[ddorwin, 2014/10/17 16:38:56]

Should this be pure virtual to force implementations to implement it rather than
having a default implementation?

[xhwang, 2014/10/17 20:32:06]

Well, most MediaKeys doesn't need this, hence the default implementation. It's
the same as GetDecryptor() above.

[ddorwin, 2014/10/18 17:05:43]

But all implementations that have this define do (or the define is too broad),
right?

[xhwang, 2014/10/20 17:59:53]

AesDecryptor is an exception. But I agree it's clearer not to have the default
impl.

Done.

+#endif
+
  private:
   DISALLOW_COPY_AND_ASSIGN(MediaKeys);
 };