Allow hw secured codecs on chromecast

chromecast/renderer/key_systems_cast.cc

Index: chromecast/renderer/key_systems_cast.cc
diff --git a/chromecast/renderer/key_systems_cast.cc b/chromecast/renderer/key_systems_cast.cc
index 76646540e7c1c519ee8c10dfb305c8787feb0ab4..3d151c5dfe038c5395c52bf5c35f87415b26e428 100644
--- a/chromecast/renderer/key_systems_cast.cc
+++ b/chromecast/renderer/key_systems_cast.cc
@@ -9,6 +9,7 @@
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "build/build_config.h"
+#include "chromecast/chromecast_features.h"
 #include "chromecast/media/base/key_systems_common.h"
 #include "components/cdm/renderer/widevine_key_system_properties.h"
 #include "media/base/eme_constants.h"
@@ -72,6 +73,46 @@ class PlayReadyKeySystemProperties : public ::media::KeySystemProperties {
 };
 #endif  // PLAYREADY_CDM_AVAILABLE
 
+#if defined(WIDEVINE_CDM_AVAILABLE)
+class CastWidevineKeySystemProperties
+    : public cdm::WidevineKeySystemProperties {
+ public:
+  CastWidevineKeySystemProperties(SupportedCodecs regular_codecs,
+                                  SupportedCodecs secure_codecs,
+                                  EmeRobustness max_audio_robustness,
+                                  EmeRobustness max_video_robustness)
+      : cdm::WidevineKeySystemProperties(
+            regular_codecs,
+            secure_codecs,
+            max_audio_robustness,
+            max_video_robustness,
+            EmeSessionTypeSupport::NOT_SUPPORTED,  // persistent-license.
+            EmeSessionTypeSupport::
+                NOT_SUPPORTED,  // persistent-release-message.
+            // Note: On Chromecast, all CDMs may have persistent state.

[ddorwin, 2016/05/27 21:33:00]

Even the audio devices?

+            EmeFeatureSupport::ALWAYS_ENABLED,     // Persistent state.
+            EmeFeatureSupport::ALWAYS_ENABLED) {}  // Distinctive identifier.
+
+  EmeConfigRule GetRobustnessConfigRule(
+      EmeMediaType media_type,
+      const std::string& requested_robustness) const override {
+    EmeConfigRule rule =
+        cdm::WidevineKeySystemProperties::GetRobustnessConfigRule(
+            media_type, requested_robustness);
+
+    if (rule != EmeConfigRule::SUPPORTED)
+      return rule;
+
+    EmeRobustness robustness = ConvertRobustness(requested_robustness);
+
+    if (robustness >= EmeRobustness::SW_SECURE_DECODE)

[ddorwin, 2016/05/27 21:33:00]

It seems that this object and method only exist to duplicate code that is
currently in a #elif defined(OS_ANDROID) block in the parent class's
implementation.

We should either extract all platform-specific logic or find a way to trigger
this check. For example, by appling "secure codecs" to all platforms and define
a min_robustness_requiring_secure_codecs_ member.

+      return EmeConfigRule::HW_SECURE_CODECS_REQUIRED;
+
+    return EmeConfigRule::SUPPORTED;
+  }
+};
+#endif  // WIDEVINE_CDM_AVAILABLE
+
 }  // namespace
 
 void AddChromecastKeySystems(
@@ -82,21 +123,23 @@ void AddChromecastKeySystems(
 #endif  // defined(PLAYREADY_CDM_AVAILABLE)
 
 #if defined(WIDEVINE_CDM_AVAILABLE)
-  ::media::SupportedCodecs codecs =
+  SupportedCodecs regular_codecs =
       ::media::EME_CODEC_MP4_AAC | ::media::EME_CODEC_MP4_AVC1 |
       ::media::EME_CODEC_WEBM_VP8 | ::media::EME_CODEC_WEBM_VP9;
-  key_systems_properties->emplace_back(new cdm::WidevineKeySystemProperties(
-      codecs,  // Regular codecs.
-#if defined(OS_ANDROID)
-      codecs,  // Hardware-secure codecs.
-#endif
-      EmeRobustness::HW_SECURE_ALL,          // Max audio robustness.
-      EmeRobustness::HW_SECURE_ALL,          // Max video robustness.
-      EmeSessionTypeSupport::NOT_SUPPORTED,  // persistent-license.
-      EmeSessionTypeSupport::NOT_SUPPORTED,  // persistent-release-message.
-      // Note: On Chromecast, all CDMs may have persistent state.
-      EmeFeatureSupport::ALWAYS_ENABLED,    // Persistent state.
-      EmeFeatureSupport::ALWAYS_ENABLED));  // Distinctive identifier.
+
+#if BUILDFLAG(DISABLE_DISPLAY)
+  SupportedCodecs secure_codecs = ::media::EME_CODEC_NONE;
+  EmeRobustness max_audio_robustness = EmeRobustness::SW_SECURE_CRYPTO;
+  EmeRobustness max_video_robustness = EmeRobustness::INVALID;

[ddorwin, 2016/05/27 21:33:00]

This will cause all configurations to fail because EMPTY > INVALID.

We might want to DCHECK in the WidevineKeySystemProperties that the values are >
INVALID. It should only be returned when the string conversion fails.

[yucliu1, 2016/06/14 00:17:45]

This is guarded under DISABLE_DISPLAY. All video related config should be
rejected.

+#else
+  SupportedCodecs secure_codecs = regular_codecs;
+  EmeRobustness max_audio_robustness = EmeRobustness::HW_SECURE_ALL;
+  EmeRobustness max_video_robustness = EmeRobustness::HW_SECURE_ALL;
+#endif  // BUILDFLAG(DISABLE_DISPLAY)
+
+  key_systems_properties->emplace_back(new CastWidevineKeySystemProperties(
+      regular_codecs, secure_codecs, max_audio_robustness,
+      max_video_robustness));
 #endif  // defined(WIDEVINE_CDM_AVAILABLE)
 }