Allow posting the CronetEngine UI Thread initialization on a custom Ui executor instead of the defa…

components/cronet/android/api/src/org/chromium/net/CronetEngine.java

Index: components/cronet/android/api/src/org/chromium/net/CronetEngine.java
diff --git a/components/cronet/android/api/src/org/chromium/net/CronetEngine.java b/components/cronet/android/api/src/org/chromium/net/CronetEngine.java
index 629adfaef31bcd5741e7ed8f9073fdba8b3a0f18..5f513f4df7e39252c3af943032d79c11d811854a 100644
--- a/components/cronet/android/api/src/org/chromium/net/CronetEngine.java
+++ b/components/cronet/android/api/src/org/chromium/net/CronetEngine.java
@@ -136,6 +136,18 @@ public abstract class CronetEngine {
         }
 
         /**
+         * Sets an {@link Executor} to be used for initialization code that needs to run
+         * on the Ui Thread.
+         * If not set, the library will be use the {@link android.os.Looper#getMainLooper()}.
+         * @param uiExecutor {@code Executor} to be used for the initialization.
+         * @return the builder to facilitate chaining.
+         */
+        public Builder setUiThreadExecutor(Executor uiExecutor) {
+            mBuilderDelegate.setUiThreadExecutor(uiExecutor);
+            return this;
+        }
+
+        /**
          * Sets whether <a href="https://www.chromium.org/quic">QUIC</a> protocol
          * is enabled. Defaults to disabled. If QUIC is enabled, then QUIC User Agent Id
          * containing application name and Cronet version is sent to the server.