title: Android shared element transition between two activities does not work
body: <p>In my app I'm trying to use the newly introduced element sharing between activities. Everything works like a charm if the shared element is with fixed position (e.g. <code>android:layout_gravity="top"</code>) but the problem comes when the view is anchored. </p>
  
  <p>My first activity looks like this:</p>
  
  <pre><code>&lt;android.support.design.widget.CoordinatorLayout
      xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:app="http://schemas.android.com/tools"
      xmlns:auto="http://schemas.android.com/apk/res-auto"
      android:layout_width="match_parent"
      android:layout_height="match_parent"&gt;
  
      &lt;android.support.v4.view.ViewPager
          android:id="@+id/pager"
          android:layout_width="match_parent"
          android:layout_height="match_parent" /&gt;
  
      &lt;android.support.design.widget.AppBarLayout
          android:id="@+id/appbar"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"&gt;
          ...
      &lt;/android.support.design.widget.AppBarLayout&gt;
  
      &lt;android.support.design.widget.FloatingActionButton
          android:id="@+id/play_all"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_gravity="bottom|right"
          android:layout_margin="24dp"/&gt;
  
  &lt;/android.support.design.widget.CoordinatorLayout&gt;
  </code></pre>
  
  <p>My second activity looks like this</p>
  
  <pre><code>&lt;android.support.design.widget.CoordinatorLayout 
      xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:auto="http://schemas.android.com/apk/res-auto"
      android:layout_width="match_parent"
      android:layout_height="match_parent"&gt;
  
      &lt;android.support.v7.widget.RecyclerView
          android:id="@+id/list"
          android:layout_width="match_parent"
          android:layout_height="match_parent" /&gt;
  
      &lt;android.support.design.widget.FloatingActionButton
          android:id="@+id/play"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_margin="16dp"
          android:elevation="10dp"
          android:src="@drawable/ic_action_play"
          auto:layout_anchor="@+id/appbar"
          android:transitionName="fab_button"
          auto:layout_anchorGravity="bottom|right" /&gt;
  
      &lt;android.support.design.widget.AppBarLayout
          android:id="@+id/appbar"
          android:layout_width="match_parent"
          android:layout_height="192dp"&gt;
          ...
      &lt;/android.support.design.widget.AppBarLayout&gt;
  
      ...
  
  &lt;/android.support.design.widget.CoordinatorLayout&gt;
  </code></pre>
  
  <p>The code I use is as follows:</p>
  
  <pre><code>Intent intent = ...;
  ActivityOptions options = ActivityOptions.makeSceneTransitionAnimation(this, view, "fab_button");
  startActivity(intent, options.toBundle());
  </code></pre>
  
  <p>If I use the <code>layout_anchor</code> and <code>layout_anchorGravity</code> attributes the transition between the two FABs is done with no animation. If the second FAB is with fixed position, it works perfectly. What am I doing wrong?</p>