Change gradle to output to the android out dir

Change-Id: I569afd35f76891390aad27b0ab75e2106cc0fe18
diff --git a/gradlew b/gradlew
index 91a7e26..d79595c 100755
--- a/gradlew
+++ b/gradlew
@@ -161,4 +161,13 @@
 eval splitJvmOpts $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS
 JVM_OPTS[${#JVM_OPTS[*]}]="-Dorg.gradle.appname=$APP_BASE_NAME"
 
-exec "$JAVACMD" "${JVM_OPTS[@]}" -classpath "$CLASSPATH" org.gradle.wrapper.GradleWrapperMain "$@"
+# Change the project's .gradle to the android out dir.
+if [[ -z "$ANDROID_CACHE_DIR" ]]; then
+  ANDROID_CACHE_DIR="$APP_HOME/../../out/host/common/tools/build/.gradle"
+fi
+
+exec "$JAVACMD" "${JVM_OPTS[@]}" \
+    -classpath "$CLASSPATH" \
+    org.gradle.wrapper.GradleWrapperMain \
+    --project-cache-dir=$ANDROID_CACHE_DIR \
+    "$@"