This reverts commit 93573de2.

Fails in the devicelab:

```
run:stderr: A problem occurred evaluating project ':app'.
run:stderr: > Could not resolve all files for configuration 'classpath'.2018-10-23T10:46:46.335864:
run:stderr:    > Could not find aapt2-proto.jar (com.android.tools.build:aapt2-proto:0.3.1).2018-10-23T10:46:46.335960:
run:stderr:      Searched in the following locations:2018-10-23T10:46:46.336048:
```