title: Gradle build failed when .xml used instead google_services.json
body: <p>I'm setting up Firebase Crashlytics. It works OK when I use google_services.json. But as we have several build variants, I prefer to use .xml instead, so I could make 2 applications at console, and 2 files in project:</p>
  <pre><code>-src/main/res/values/google_services.xml (for all builds, corresponds to test app at firebase)
  -src/release/res/values/google_services.xml (for prod-release build)
  </code></pre>
  <p>Also I removed apply plugin: 'com.google.gms.google-services'</p>
  <p>But my builds fails for all release tasks:</p>
  <pre><code>assembleTestRelease
  assembleStageRelease
  </code></pre>
  <p>Reason is in</p>
  <pre><code>minifyEnabled true
  shrinkResources true
  </code></pre>
  <p>Before migration on Firebase Crashlytic (with Fabric) it worked fine.</p>
  <p>Error:</p>
  <pre><code>* Exception is:
  org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':app:uploadCrashlyticsMappingFileTestRelease'.
      at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$3.accept(ExecuteActionsTaskExecuter.java:151)
      ...
  Caused by: org.gradle.api.GradleException: Crashlytics could not find the resource file generated by Google Services. You may need to execute the :process&lt;Variant&gt;GoogleServices Task. Please check your Firebase project configuration (https://firebase.google.com/docs/android/setup). 
      at com.google.firebase.crashlytics.buildtools.gradle.ProjectVariantState.getGoogleAppId(ProjectVariantState.groovy:195)
      ... 35 more
  </code></pre>