Adds initial key systems support for Chromecast.

chromecast/shell/renderer/key_systems_cast.cc

+// Copyright 2014 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.
+
+#include "chromecast/shell/renderer/key_systems_cast.h"
+
+#include <string>
+
+#include "base/command_line.h"
+#include "base/logging.h"
+#include "chromecast/media/base/key_systems_common.h"
+#include "content/public/common/eme_codec.h"
+
+#include "widevine_cdm_version.h" // In SHARED_INTERMEDIATE_DIR.
+
+using content::KeySystemInfo;
+
+namespace {
+
+// Return |name|'s parent key system.
+std::string GetDirectParentName(const std::string& name) {
+  int last_period = name.find_last_of('.');
+  DCHECK_GT(last_period, 0);
+  return name.substr(0, last_period);
+}
+
+void AddKeySystemWithCodecs(
+    const std::string& key_system_name,
+    bool add_parent_name,
+    std::vector<KeySystemInfo>* concrete_key_systems) {
+  KeySystemInfo info(key_system_name);
+
+  if (add_parent_name)
+    info.parent_key_system = GetDirectParentName(key_system_name);
+
+  info.supported_codecs = content::EME_CODEC_MP4_ALL;
+
+  concrete_key_systems->push_back(info);
+}
+
+}  // namespace anonymous
+
+namespace content {
+
+void AddChromecastKeySystems(std::vector<KeySystemInfo>* key_systems_info) {
+  // Chromecast supports unprefixed clearkey, which upstream rewrites to

[ddorwin, 2014/09/13 03:27:07]

I don't think this comment is correct. Are you saying the
webkitGenerateKeyRequest() expects "org.w3.clearkey" without the "webkit-"?

Hmm, that will be a problem. Maybe you should put a Chromecast-specific fix in
these methods:
https://code.google.com/p/chromium/codesearch#chromium/src/content/renderer/m...

[gunsch, 2014/09/15 21:43:38]

Ah, yes: we're expecting to handle "org.w3.clearkey" used in conjunction with
"webkitGenerateKeyRequest". Rewrote this comment to clarify, and added a more
explicit TODO (also in key_systems_common.cc).

The methods you linked to are exactly what this is trying to work around.
However, we have been explicitly asked to not have any sort of "CHROMECAST"
C-define in the codebase, so we don't have any "Chromecast-specific fixes" in
the rest of Chromium.

+  // "unsupported-org.w3.clearkey".
+  // TODO(gunsch): remove this when upstream supports unprefixed clearkey.
+  // See: crbug/393397
+  AddKeySystemWithCodecs(media::kUnsupportedClearKeySystem,
+                         false,
+                         key_systems_info);
+
+#if defined(WIDEVINE_CDM_AVAILABLE)
+  AddKeySystemWithCodecs(kWidevineKeySystem, true, key_systems_info);

[ddorwin, 2014/09/13 03:27:07]

It may not be useful, but FYI:
https://code.google.com/p/chromium/codesearch#chromium/src/components/cdm/ren...

[gunsch, 2014/09/15 21:43:38]

Thanks! That is useful. Updated.

+#endif
+
+#if defined(PLAYREADY_CDM_AVAILABLE)
+  for (size_t i = 0; media::kPlayreadyKeySystems[i] != NULL; i++) {
+    AddKeySystemWithCodecs(media::kPlayreadyKeySystems[i],
+                           false,
+                           key_systems_info);
+  }
+#endif
+}
+
+}  // namespace content