Implement Chromium side of MediaKeys.isTypeSupported().

components/cdm/renderer/android_key_systems.cc

Index: components/cdm/renderer/android_key_systems.cc
diff --git a/components/cdm/renderer/android_key_systems.cc b/components/cdm/renderer/android_key_systems.cc
index 99bc2bb5149db002453abca79267d494d2e57f7b..5aacc496caf69afd4f89d4ee8866c6a9329a3188 100644
--- a/components/cdm/renderer/android_key_systems.cc
+++ b/components/cdm/renderer/android_key_systems.cc
@@ -10,6 +10,7 @@
 #include "base/logging.h"
 #include "components/cdm/common/cdm_messages_android.h"
 #include "components/cdm/renderer/widevine_key_systems.h"
+#include "content/public/common/eme_constants.h"
 #include "content/public/renderer/render_thread.h"
 
 #include "widevine_cdm_version.h"  // In SHARED_INTERMEDIATE_DIR.
@@ -65,6 +66,12 @@ void AddAndroidPlatformKeySystems(
     if (response.compositing_codecs != content::EME_CODEC_NONE) {
       KeySystemInfo info(*it);
       info.supported_codecs = response.compositing_codecs;
+      // Assume that WebM and CENC are supported by platform CDMs. |KeySystems|

[ddorwin, 2014/09/23 22:48:15]

... CDMs that support their respective containers. KeySystems will remove the
type if the MIME type is not supported.
^ Is that correct? Or is it filtered somewhere else?

[ddorwin, 2014/09/23 22:48:15]

I think '|' is usually used for parameters and maybe members. Not classes,
AFAIK.

[sandersd (OOO until July 31), 2014/09/24 22:22:32]

No, it just returns false for IsSupported queries, which is all that this data
is used for so far.

[sandersd (OOO until July 31), 2014/09/24 22:22:33]

Done.

+      // handles validating |init_data_type|/|container| mappings.
+      info.supported_init_data_types = content::EME_INIT_DATA_TYPE_WEBM;
+#if defined(USE_PROPRIETARY_CODECS)
+      info.supported_init_data_types |= content::EME_INIT_DATA_TYPE_CENC;
+#endif  // defined(USE_PROPRIETARY_CODECS)
       concrete_key_systems->push_back(info);
     }
   }