title: DataBinding library include don't work without variable
body: <p>As George Mount <a href="https://stackoverflow.com/a/32958608/1546975">said</a>  starting from 1.0-rc4 we no longer need the variable in include when using data binding:</p>
  
  <p>buttons.xml:</p>
  
  <pre><code>&lt;layout xmlns:andr...&gt;
     &lt;Button
      android:id="@+id/button"
      ...." /&gt;
  </code></pre>
  
  <p>main.xml:</p>
  
  <pre><code>&lt;layout xmlns:andr...
  ...
      &lt;include layout="@layout/buttons"
              android:id="@+id/buttons"/&gt;
  ....
  </code></pre>
  
  <p>But I tried it and get error:</p>
  
  <p><strong>Error:(10, 31) Identifiers must have user defined types from the XML file. toolbarViewModel is missing it</strong> </p>
  
  <p>I have the included toolbar:</p>
  
  <pre><code>&lt;layout xmlns:android="http://schemas.android.com/apk/res/android"
          xmlns:app="http://schemas.android.com/apk/res-auto"&gt;
  
      &lt;data class="LoginPhoneFragmentBinding"&gt;
  
          &lt;variable
              name="toolbarViewModel"
              type="ru.mobileup.myalarm2.binding.ToolbarViewModel"/&gt;
      &lt;/data&gt;
  
      &lt;FrameLayout
          android:layout_width="match_parent"
          android:layout_height="match_parent"&gt;
  
          &lt;include
               layout="@layout/toolbar"
               android:id="@+id/toolbarBinding"/&gt;
  </code></pre>
  
  <p>And toolbar layout is:</p>
  
  <pre><code>&lt;layout xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:app="http://schemas.android.com/apk/res-auto"&gt;
  &lt;android.support.v7.widget.Toolbar
      android:id="@+id/toolbar"
      android:layout_width="match_parent"
      android:layout_height="?attr/actionBarSize"
      android:background="@color/primary"
      android:theme="@style/ToolbarThemeOverlay"
      app:navigationIcon="@{toolbarViewModel.navigationIconResId}"
      app:navigationOnClickListener="@{toolbarViewModel.navigationOnClickListener}"
      app:title="@{toolbarViewModel.title}"
      app:menu="@{toolbarViewModel.menuResId}"
      app:menuListener="@{toolbarViewModel.onMenuItemClickListener}"/&gt;
  </code></pre>
  
  <p></p>
  
  <p><strong>What is wrong?</strong></p>
  
  <p><em>Note: I know that with passed variable all works fine. I trying to figure out how use that George mentioned.</em></p>