android: switch to the Hermes JavaScript engine

android/app/proguard-rules.pro

 # ^^^ We added the above when we switched minifyEnabled on.
 
 # Rule to avoid build errors related to SVGs.
--keep public class com.horcrux.svg.** {*;}
+-keep public class com.horcrux.svg.** {*;}
+
+# Hermes
+-keep class com.facebook.hermes.unicode.** { *; }
+

android/build.gradle

         jcenter()
         // React Native (JS, Obj-C sources, Android binaries) is installed from npm.
         maven { url "$rootDir/../node_modules/react-native/android" }
-        // Android JSC is installed from npm.
-        maven { url("$rootDir/../node_modules/jsc-android/dist") }
     }
 
     // Make sure we use the react-native version in node_modules and not the one

android/sdk/build.gradle

 
     //noinspection GradleDynamicVersion
     api 'com.facebook.react:react-native:+'
-    //noinspection GradleDynamicVersion
-    implementation 'org.webkit:android-jsc:+'
+
+    // Hermes JS engine
+    def hermesPath = "../../node_modules/hermes-engine/android/"
+    debugImplementation files(hermesPath + "hermes-debug.aar")
+    releaseImplementation files(hermesPath + "hermes-release.aar")
 
     implementation 'com.dropbox.core:dropbox-core-sdk:3.0.8'
     implementation 'com.jakewharton.timber:timber:4.7.1'

android/sdk/src/main/java/org/jitsi/meet/sdk/ReactInstanceManagerHolder.java

 import android.app.Activity;
 import androidx.annotation.Nullable;
 
+import com.facebook.hermes.reactexecutor.HermesExecutorFactory;
 import com.facebook.react.ReactInstanceManager;
 import com.facebook.react.ReactPackage;
 import com.facebook.react.bridge.NativeModule;
 import com.facebook.react.bridge.ReactApplicationContext;
 import com.facebook.react.common.LifecycleState;
 import com.facebook.react.devsupport.DevInternalSettings;
-import com.facebook.react.jscexecutor.JSCExecutorFactory;
 import com.facebook.react.modules.core.DeviceEventManagerModule;
 import com.facebook.react.uimanager.ViewManager;
 import com.facebook.soloader.SoLoader;
 import com.oney.WebRTCModule.RTCVideoViewManager;
 import com.oney.WebRTCModule.WebRTCModule;
 
-import org.jitsi.meet.sdk.log.JitsiMeetLogger;
 import org.webrtc.SoftwareVideoDecoderFactory;
 import org.webrtc.SoftwareVideoEncoderFactory;
 import org.webrtc.VideoDecoderFactory;
             // Ignore any error, the module is not compiled when LIBRE_BUILD is enabled.
         }
 
-        // Keep on using JSC, the jury is out on Hermes.
-        JSCExecutorFactory jsFactory
-            = new JSCExecutorFactory("", "");
+        // Use the Hermes JavaScript engine.
+        HermesExecutorFactory jsFactory = new HermesExecutorFactory();
 
         reactInstanceManager
             = ReactInstanceManager.builder()