media: Add kWidevineAv1ForceSupportForTesting feature

This is useful for encrypted AV1 testing on platforms that doesn't not
support component updated CDM (where codec support is read from CDM
manifest).

Bug: 953507
Change-Id: If43dc7d5fcbb8a8e69777831a9a3e52593f77ff2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1747232Reviewed-by: John Rummell <jrummell@chromium.org>
Commit-Queue: Xiaohan Wang <xhwang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#686184}

components/cdm/renderer/widevine_key_system_properties.cc

@@ -99,19 +99,27 @@ EmeConfigRule WidevineKeySystemProperties::GetEncryptionSchemeConfigRule(
     return EmeConfigRule::NOT_SUPPORTED;
 }
 
+static SupportedCodecs OverrideAv1SupportIfNeeded(SupportedCodecs codecs) {
+  auto result = codecs;
+
+  // Enable AV1 if force-support is enabled.
+  if (base::FeatureList::IsEnabled(media::kWidevineAv1ForceSupportForTesting))
+    result |= media::EME_CODEC_AV1;
+
+  // Disable AV1 if the master switch kWidevineAv1 is disabled.
+  if (!base::FeatureList::IsEnabled(media::kWidevineAv1))
+    result &= ~media::EME_CODEC_AV1;
+
+  return result;
+}
+
 SupportedCodecs WidevineKeySystemProperties::GetSupportedCodecs() const {
-  // Disable AV1 if feature kWidevineAv1 is disabled
-  return base::FeatureList::IsEnabled(media::kWidevineAv1)
-             ? codecs_
-             : (codecs_ & ~media::EME_CODEC_AV1);
+  return OverrideAv1SupportIfNeeded(codecs_);
 }
 
 SupportedCodecs WidevineKeySystemProperties::GetSupportedHwSecureCodecs()
     const {
-  // Disable AV1 if feature kWidevineAv1 is disabled
-  return base::FeatureList::IsEnabled(media::kWidevineAv1)
-             ? hw_secure_codecs_
-             : (hw_secure_codecs_ & ~media::EME_CODEC_AV1);
+  return OverrideAv1SupportIfNeeded(hw_secure_codecs_);
 }
 
 EmeConfigRule WidevineKeySystemProperties::GetRobustnessConfigRule(

media/base/media_switches.cc

@@ -348,6 +348,12 @@ const base::Feature kHardwareSecureDecryption{
 const base::Feature kWidevineAv1{"WidevineAv1",
                                  base::FEATURE_ENABLED_BY_DEFAULT};
 
+// Forces to support encrypted AV1 in EME requestMediaKeySystemAccess() query by
+// Widevine key system even if the underlying Widevine CDM doesn't support it.
+// No effect if "WidevineAv1" feature is disabled.
+const base::Feature kWidevineAv1ForceSupportForTesting{
+    "WidevineAv1ForceSupportForTesting", base::FEATURE_DISABLED_BY_DEFAULT};
+
 // Enables handling of hardware media keys for controlling media.
 const base::Feature kHardwareMediaKeyHandling{
   "HardwareMediaKeyHandling",

media/base/media_switches.h

@@ -140,6 +140,7 @@ MEDIA_EXPORT extern const base::Feature kVaapiVP9Encoder;
 MEDIA_EXPORT extern const base::Feature kVp9kSVCHWDecoding;
 MEDIA_EXPORT extern const base::Feature kVideoBlitColorAccuracy;
 MEDIA_EXPORT extern const base::Feature kWidevineAv1;
+MEDIA_EXPORT extern const base::Feature kWidevineAv1ForceSupportForTesting;
 
 #if defined(OS_ANDROID)
 MEDIA_EXPORT extern const base::Feature kMediaControlsExpandGesture;