Inject plugins before evaluating Gradle project (#13827)

packages/flutter_tools/lib/src/android/gradle.dart

@@ -86,6 +86,7 @@ Future<GradleProject> _gradleProject() async {
 Future<GradleProject> _readGradleProject() async {
   final String gradle = await _ensureGradle();
   updateLocalProperties();
+  injectPlugins();
   try {
     final Status status = logger.startProgress('Resolving dependencies...', expectSlowOperation: true);
     final RunResult runResult = await runCheckedAsync(
@@ -223,8 +224,6 @@ Future<Null> buildGradleProject(BuildInfo buildInfo, String target) async {
   // update local.properties, in case we want to use it in the future.
   updateLocalProperties(buildInfo: buildInfo);
 
-  injectPlugins();
-
   final String gradle = await _ensureGradle();
 
   switch (flutterPluginVersion) {