Add API for custom library loading

components/cronet/android/test/cronet_url_request_context_config_test.cc

Index: components/cronet/android/test/cronet_url_request_context_config_test.cc
diff --git a/components/cronet/android/test/cronet_url_request_context_config_test.cc b/components/cronet/android/test/cronet_url_request_context_config_test.cc
index c879fe97fd78d41f0117f9276893200016f51169..b7bf7c01dfe5d922d5f67a61647d31b62df4b053 100644
--- a/components/cronet/android/test/cronet_url_request_context_config_test.cc
+++ b/components/cronet/android/test/cronet_url_request_context_config_test.cc
@@ -45,8 +45,12 @@ static void VerifyUrlRequestContextConfig(
            base::android::ConvertJavaStringToUTF8(env, jstorage_path));
 }
 
+static void LibraryExists(JNIEnv* env, const JavaParamRef<jclass>& jcaller) {
+  return;
+}
+
 bool RegisterCronetUrlRequestContextConfigTest(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
-}  // namespace cronet
+}  // namespace cronet