Android: Instrumentation tests in gradle

build/android/gradle/java.jinja

 {# Copyright 2016 The Chromium Authors. All rights reserved. #}
 {# Use of this source code is governed by a BSD-style license that can be #}
 {# found in the LICENSE file. #}
 // Generated by //build/android/generate_gradle.py
 
 apply plugin: "java"
 {% if template_type == 'java_binary' %}
 apply plugin: "application"
 {% endif %}
 
 sourceSets {
     main {
         java.srcDirs = [
-{% for path in java_dirs %}
+{% for path in main.java_dirs %}
             "{{ path }}",
 {% endfor %}
         ]
     }
 }
 
 sourceCompatibility = JavaVersion.VERSION_1_7
 targetCompatibility = JavaVersion.VERSION_1_7
 
 {% if template_type == 'java_binary' %}
 mainClassName = "{{ main_class }}"
 applicationName = "{{ target_name }}"
 {% endif %}
 {% if template_type in ('java_binary', 'java_library') %}
 archivesBaseName = "{{ target_name }}"
 {% endif %}
 
 {% include 'dependencies.jinja' %}