[Cronet] Expose ExperimentalCronetEngine.Builder.getBuilderDelegate() for tests

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

Index: components/cronet/android/api/src/org/chromium/net/ExperimentalCronetEngine.java
diff --git a/components/cronet/android/api/src/org/chromium/net/ExperimentalCronetEngine.java b/components/cronet/android/api/src/org/chromium/net/ExperimentalCronetEngine.java
index 6fc67f4e5dca45fe487bb39ffeebecf393797967..4535fe155ed809e10b2aca4b7dab116e140a3ed8 100644
--- a/components/cronet/android/api/src/org/chromium/net/ExperimentalCronetEngine.java
+++ b/components/cronet/android/api/src/org/chromium/net/ExperimentalCronetEngine.java
@@ -181,8 +181,12 @@ public abstract class ExperimentalCronetEngine extends CronetEngine {
             return this;
         }
 
+        /**
+         * Returns delegate, only for testing.
+         * @hide
+         */
         @VisibleForTesting
-        ICronetEngineBuilder getBuilderDelegate() {
+        public ICronetEngineBuilder getBuilderDelegate() {
             return mBuilderDelegate;
         }