title: DataBindingInfo.java being regenerated at every code change
body: <p>I'm working on fairly large, multi module Android project which is using Data Binding, Dagger 2 and Java mixed with Kotlin.</p>
  
  <p>After the slightest change in the project "code" files (.java and .kt files including activities, custom classes etc) there is a huge (up to 2 minutes) build time. It happens even when I'm adding changes like a new line or modify one character in comment. </p>
  
  <p>I did run Gradle script with --info parameter and got the following hint, it "hangs" on the following task:</p>
  
  <blockquote>
    <p>Build cache key for task ':AppName:kaptDebugKotlin' is
    1a3a53e5f9b0934ab50a25c0133055f2 Up-to-date check for task
    ':AppName:kaptDebugKotlin' took 0.0 secs. It is not up-to-date
    because:   Input property 'source' file
    /Users/username/Android/project-directory/AppName/build/generated/source/dataBinding/debug/android/databinding/layouts/DataBindingInfo.java
    has changed.   Input property 'source' file
    /Users/username/Android/project-directory/AppName/src/main/java/com/package/to/my/activity/SomeActivity.java
    has changed.</p>
  </blockquote>
  
  <p>The DataBindingInfo.java is generated file which contains just a buildId:</p>
  
  <pre><code>package android.databinding.layouts;
  
  import android.databinding.BindingBuildInfo;
  
  @BindingBuildInfo(buildId="23567c57-d3c8-4999-bc79-6211351c7d89")
  public class DataBindingInfo {}
  </code></pre>
  
  <p>And the buildId hash changes each time there is any change in the code.</p>
  
  <p>The project uses Crashlytics, I disabled it for debug builds though. </p>
  
  <p>What might be the cause of this behaviour?</p>
  
  <p>EDIT: buildId is getting regenerated on the project even when the Android Studio is closed and I'm doing the changes in the external editor and running builds from command line.</p>