Implement Chromium side of MediaKeys.isTypeSupported().

content/renderer/media/crypto/key_systems.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_RENDERER_MEDIA_CRYPTO_KEY_SYSTEMS_H_
 #define CONTENT_RENDERER_MEDIA_CRYPTO_KEY_SYSTEMS_H_
 
 #include <string>
 #include <vector>
 
 #include "base/memory/scoped_ptr.h"
 #include "content/common/content_export.h"
 
 namespace content {
 
 // Prefixed EME API only supports prefixed (webkit-) key system name for
 // certain key systems. But internally only unprefixed key systems are
 // supported. The following two functions help convert between prefixed and
 // unprefixed key system names.
 
 // Gets the unprefixed key system name for |key_system|.
 std::string GetUnprefixedKeySystemName(const std::string& key_system);
 
 // Gets the prefixed key system name for |key_system|.
 std::string GetPrefixedKeySystemName(const std::string& key_system);
 
+bool IsSaneInitDataTypeWithContainer(

[ddorwin, 2014/09/23 22:48:17]

This is really an implementation detail of this class - we don't add every
combination in our table. Thus, this should probably be handled internally.
However, we don't have a function that checks the type and container, so I guess
we'll have to leave it exposed (unless/until the spec is updated to separate
them :) ).

[ddorwin, 2014/09/23 22:48:17]

This probably deserves a comment:
// Returns false if a container-specific |init_data_type| is specified with an
inappropriate container.

[sandersd (OOO until July 31), 2014/09/24 22:22:34]

Done.

[sandersd (OOO until July 31), 2014/09/24 22:22:34]

Acknowledged.

+    const std::string& init_data_type,

[ddorwin, 2014/09/23 22:48:17]

I was thinking we should convert IDT (and maybe container) to an enum to pass
around. (In a separate CL/effort.) WDYT?

[sandersd (OOO until July 31), 2014/09/24 22:22:34]

This makes sense; we could add APIs here to turn the string into enum values,
then use those values everywhere else.

For this particular method it doesn't make much difference.

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

Even better, the strings should never reach Chromium. :)

+    const std::string& container);
+
+bool IsSupportedKeySystem(const std::string& key_system);
+
+bool IsSupportedKeySystemWithInitDataType(
+    const std::string& key_system,
+    const std::string& init_data_type);
+
 // Returns whether |key_system| is a real supported key system that can be
 // instantiated.
 // Abstract parent |key_system| strings will return false.
 // Call IsSupportedKeySystemWithMediaMimeType() to determine whether a
 // |key_system| supports a specific type of media or to check parent key
 // systems.
 CONTENT_EXPORT bool IsConcreteSupportedKeySystem(const std::string& key_system);
 
 // Returns whether |key_sytem| supports the specified media type and codec(s).
 CONTENT_EXPORT bool IsSupportedKeySystemWithMediaMimeType(
@@ skipping 16 matching lines @@
 
 #if defined(UNIT_TEST)
 // Helper functions to add container/codec types for testing purposes.
 CONTENT_EXPORT void AddContainerMask(const std::string& container, uint32 mask);
 CONTENT_EXPORT void AddCodecMask(const std::string& codec, uint32 mask);
 #endif  // defined(UNIT_TEST)
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_CRYPTO_KEY_SYSTEMS_H_