Implement Chromium side of MediaKeys.isTypeSupported().

content/public/renderer/key_system_info.h

Index: content/public/renderer/key_system_info.h
diff --git a/content/public/renderer/key_system_info.h b/content/public/renderer/key_system_info.h
index 8eb2e573c4806e7e4fb1284bbe7929155628450c..28a3584eae1166e142776964afa9e8abd9a992bc 100644
--- a/content/public/renderer/key_system_info.h
+++ b/content/public/renderer/key_system_info.h
@@ -11,7 +11,7 @@
 #include "base/basictypes.h"
 #include "base/containers/hash_tables.h"
 #include "content/common/content_export.h"
-#include "content/public/common/eme_codec.h"
+#include "content/public/common/eme_constants.h"
 
 // Definitions:
 // * Key system
@@ -41,6 +41,9 @@ struct CONTENT_EXPORT KeySystemInfo {
   // Specifies codecs supported by |key_system|.
   SupportedCodecs supported_codecs;
 
+  // Specifies registered initialization data types supported by |key_system|.
+  SupportedInitDataTypes supported_init_data_types;

[ddorwin, 2014/09/27 00:41:24]

Hmm. This order is inconsistent with all the uses, right? We should probably
change it here too.

[sandersd (OOO until July 31), 2014/09/29 17:49:23]

Done.

+
   // A hierarchical parent for |key_system|. This value can be used to check
   // supported types but cannot be used to instantiate a MediaKeys object.
   // Only one parent key system is currently supported per concrete key system.