Make the libaom AV1 encoder optional in RTCDefaultVideoEncoderFactory.

This is a partial revert of: https://webrtc-review.googlesource.com/c/src/+/262814

skip_shebang_check=True

bug: webrtc:13573
Change-Id: I08282df91446efa79ca86cc8dfe3b6daeb4eec9a
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/264543
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Philip Eliasson <philipel@webrtc.org>
Reviewed-by: Peter Hanspers <peterhanspers@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#37074}

sdk/BUILD.gn

@@ -6,6 +6,7 @@
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
+import("//third_party/libaom/options.gni")
 import("../webrtc.gni")
 if (is_ios) {
   import("//build/config/ios/ios_sdk.gni")
@@ -748,8 +749,13 @@ if (is_ios || is_mac) {
         ":wrapped_native_codec_objc",
         "../media:rtc_media_base",
         "../modules/video_coding/codecs/av1:libaom_av1_decoder",
-        "../modules/video_coding/codecs/av1:libaom_av1_encoder",
       ]
+
+      defines = []
+      if (enable_libaom) {
+        defines += [ "RTC_USE_LIBAOM_AV1_ENCODER" ]
+        deps += [ "../modules/video_coding/codecs/av1:libaom_av1_encoder" ]
+      }
     }
 
     # Build the PeerConnectionFactory without audio/video support.

sdk/objc/api/video_codec/RTCVideoEncoderAV1.h

@@ -22,4 +22,6 @@ RTC_OBJC_EXPORT
  */
 + (id<RTC_OBJC_TYPE(RTCVideoEncoder)>)av1Encoder;
 
++ (bool)isSupported;
+
 @end

sdk/objc/api/video_codec/RTCVideoEncoderAV1.mm

@@ -15,15 +15,28 @@
 #import "RTCVideoEncoderAV1.h"
 #import "RTCWrappedNativeVideoEncoder.h"
 
-#include "modules/video_coding/codecs/av1/libaom_av1_encoder.h"
+#if defined(RTC_USE_LIBAOM_AV1_ENCODER)
+#include "modules/video_coding/codecs/av1/libaom_av1_encoder.h"  // nogncheck
+#endif
 
 @implementation RTC_OBJC_TYPE (RTCVideoEncoderAV1)
 
 + (id<RTC_OBJC_TYPE(RTCVideoEncoder)>)av1Encoder {
+#if defined(RTC_USE_LIBAOM_AV1_ENCODER)
   std::unique_ptr<webrtc::VideoEncoder> nativeEncoder(webrtc::CreateLibaomAv1Encoder());
-
   return [[RTC_OBJC_TYPE(RTCWrappedNativeVideoEncoder) alloc]
       initWithNativeEncoder:std::move(nativeEncoder)];
+#else
+  return nil;
+#endif
+}
+
++ (bool)isSupported {
+#if defined(RTC_USE_LIBAOM_AV1_ENCODER)
+  return true;
+#else
+  return false;
+#endif
 }
 
 @end

sdk/objc/components/video_codec/RTCDefaultVideoEncoderFactory.m

@@ -55,7 +55,10 @@
         addObject:[[RTC_OBJC_TYPE(RTCVideoCodecInfo) alloc] initWithName:kRTCVideoCodecVp9Name]];
   }
 
-  [result addObject:[[RTC_OBJC_TYPE(RTCVideoCodecInfo) alloc] initWithName:kRTCVideoCodecAv1Name]];
+  if ([RTC_OBJC_TYPE(RTCVideoEncoderAV1) isSupported]) {
+    [result
+        addObject:[[RTC_OBJC_TYPE(RTCVideoCodecInfo) alloc] initWithName:kRTCVideoCodecAv1Name]];
+  }
 
   return result;
 }
@@ -68,7 +71,8 @@
   } else if ([info.name isEqualToString:kRTCVideoCodecVp9Name] &&
              [RTC_OBJC_TYPE(RTCVideoEncoderVP9) isSupported]) {
     return [RTC_OBJC_TYPE(RTCVideoEncoderVP9) vp9Encoder];
-  } else if ([info.name isEqualToString:kRTCVideoCodecAv1Name]) {
+  } else if ([info.name isEqualToString:kRTCVideoCodecAv1Name] &&
+             [RTC_OBJC_TYPE(RTCVideoEncoderAV1) isSupported]) {
     return [RTC_OBJC_TYPE(RTCVideoEncoderAV1) av1Encoder];
   }