Bug 1898344 - part5 : implement MediaCapabilitiesDecodingInfo. r=media-playback-reviewers,webidl,smaug,padenot

This patch implement a MediaKeySystemAccess in
MediaCapabilitiesDecodingInfo per spec [1], but we haven't implemented
the configuration part yet.

Currently Chromium doesn't implement the configuration [2] and WebKit
[3] only implements the configuration but no key system access.

[1] https://www.w3.org/TR/media-capabilities/#media-capabilities-interface
[2] https://bit.ly/3RcwuaV
[3] https://searchfox.org/wubkat/source/Source/WebCore/Modules/mediacapabilities/MediaCapabilitiesDecodingInfo.idl

Differential Revision: https://phabricator.services.mozilla.com/D212324

dom/media/mediacapabilities/MediaCapabilities.cpp

@@ -200,7 +200,7 @@ void MediaCapabilities::CreateMediaCapabilitiesDecodingInfo(
   }
 
   if (!supported) {
-    MediaCapabilitiesInfo info;
+    MediaCapabilitiesDecodingInfo info;
     info.mSupported = false;
     info.mSmooth = false;
     info.mPowerEfficient = false;
@@ -256,6 +256,9 @@ void MediaCapabilities::CreateMediaCapabilitiesDecodingInfo(
     tracks.AppendElements(std::move(audioTracks));
   }
 
+  // TODO : implement 'Check Encrypted Decoding Support'
+  // https://www.w3.org/TR/media-capabilities/#is-encrypted-decode-supported
+
   using CapabilitiesPromise = MozPromise<MediaCapabilitiesInfo, MediaResult,
                                          /* IsExclusive = */ true>;
   nsTArray<RefPtr<CapabilitiesPromise>> promises;
@@ -283,7 +286,7 @@ void MediaCapabilities::CreateMediaCapabilitiesDecodingInfo(
               return CapabilitiesPromise::CreateAndReject(NS_ERROR_FAILURE,
                                                           __func__);
             }
-            MediaCapabilitiesInfo info;
+            MediaCapabilitiesDecodingInfo info;
             info.mSupported = true;
             info.mSmooth = true;
             info.mPowerEfficient = true;
@@ -358,7 +361,7 @@ void MediaCapabilities::CreateMediaCapabilitiesDecodingInfo(
                             p = CapabilitiesPromise::CreateAndReject(
                                 std::move(aValue.RejectValue()), __func__);
                           } else if (shouldResistFingerprinting) {
-                            MediaCapabilitiesInfo info;
+                            MediaCapabilitiesDecodingInfo info;
                             info.mSupported = true;
                             info.mSmooth = true;
                             info.mPowerEfficient = false;
@@ -386,7 +389,7 @@ void MediaCapabilities::CreateMediaCapabilitiesDecodingInfo(
                                     bool smooth = score < 0 || score >
                                       StaticPrefs::
                                         media_mediacapabilities_drop_threshold();
-                                    MediaCapabilitiesInfo info;
+                                    MediaCapabilitiesDecodingInfo info;
                                     info.mSupported = true;
                                     info.mSmooth = smooth;
                                     info.mPowerEfficient = powerEfficient;
@@ -404,7 +407,7 @@ void MediaCapabilities::CreateMediaCapabilitiesDecodingInfo(
                               // decoding is hardware accelerated it will be
                               // smooth and power efficient, otherwise we use
                               // the benchmark to estimate
-                              MediaCapabilitiesInfo info;
+                              MediaCapabilitiesDecodingInfo info;
                               info.mSupported = true;
                               info.mSmooth = true;
                               info.mPowerEfficient = true;
@@ -436,7 +439,7 @@ void MediaCapabilities::CreateMediaCapabilitiesDecodingInfo(
                                   smooth = needed > 2;
                                 }
                               }
-                              MediaCapabilitiesInfo info;
+                              MediaCapabilitiesDecodingInfo info;
                               info.mSupported = true;
                               info.mSmooth = smooth;
                               info.mPowerEfficient = powerEfficient;
@@ -494,7 +497,7 @@ void MediaCapabilities::CreateMediaCapabilitiesDecodingInfo(
                         aValue) {
                holder->Complete();
                if (aValue.IsReject()) {
-                 MediaCapabilitiesInfo info;
+                 MediaCapabilitiesDecodingInfo info;
                  info.mSupported = false;
                  info.mSmooth = false;
                  info.mPowerEfficient = false;
@@ -510,7 +513,7 @@ void MediaCapabilities::CreateMediaCapabilitiesDecodingInfo(
                  smooth &= capability.mSmooth;
                  powerEfficient &= capability.mPowerEfficient;
                }
-               MediaCapabilitiesInfo info;
+               MediaCapabilitiesDecodingInfo info;
                info.mSupported = true;
                info.mSmooth = smooth;
                info.mPowerEfficient = powerEfficient;

dom/webidl/MediaCapabilities.webidl

@@ -94,10 +94,17 @@ dictionary MediaCapabilitiesInfo {
   required boolean powerEfficient;
 };
 
+// https://w3c.github.io/media-capabilities/#dictdef-mediacapabilitiesinfo
+dictionary MediaCapabilitiesDecodingInfo : MediaCapabilitiesInfo {
+  // This doesn't match the spec, see https://github.com/w3c/media-capabilities/issues/219
+  required MediaKeySystemAccess? keySystemAccess;
+  // TODO : implement configuration
+};
+
 [Exposed=(Window, Worker)]
 interface MediaCapabilities {
   [NewObject]
-  Promise<MediaCapabilitiesInfo> decodingInfo(MediaDecodingConfiguration configuration);
+  Promise<MediaCapabilitiesDecodingInfo> decodingInfo(MediaDecodingConfiguration configuration);
   [NewObject]
   Promise<MediaCapabilitiesInfo> encodingInfo(MediaEncodingConfiguration configuration);
 };