title: ConstraintLayout Placeholder view does not override dimensions
body: <p>I am trying to use the new constraint layout placeholder, but I am getting difficulties due to the fact that it won't work properly if width/height values other than 0 will be supplied to placeholder. </p>
  
  <p>This is my child view that should inject a view into the template. Notice that width and height is set to match_constraint and wrap_content</p>
  
  <pre><code>   &lt;android.support.constraint.ConstraintLayout
              android:layout_width="match_parent"
              android:layout_height="match_parent"&gt;
  
              &lt;TextView
                  android:id="@+id/dialog_content"
                  android:layout_width="0dp"
                  android:layout_height="wrap_content"
                  tools:layout_height="30dp" /&gt;
  
              &lt;include
                  layout="@layout/view_full_screen_dialog_template"/&gt;
      &lt;/android.support.constraint.ConstraintLayout&gt;
  </code></pre>
  
  <p>This is code I am using for my Placeholder</p>
  
  <pre><code>  &lt;android.support.constraint.Placeholder
          android:id="@+id/template_dialog_content"
          android:layout_width="0dp"
          android:layout_height="wrap_content"
          tools:text="asasdasdasdasdasdasdasdasdasdasdf"
          app:content="@+id/dialog_content"
          app:layout_constraintBottom_toTopOf="@+id/w_buttons"
          app:layout_constraintEnd_toEndOf="parent"
          app:layout_constraintStart_toStartOf="parent"
          app:layout_constraintTop_toBottomOf="@+id/dialog_title" /&gt;
  </code></pre>
  
  <p>As you can see I have laout_height set to wrap_content too and this(somewhy) forces layout in designer to be streched all across the view. </p>
  
  <p>Problem is that the text view acts simply weird, getting cut, only taking 2dp of content. If i'd set width/height for placeholder to 0dp, it would work fine. </p>
  
  <p>TL;DR can placeholder width/height values be different than 0 for it to work properly? And can they be overriden? </p>