title: Collapsing Toolbar title not centered
body: <p>My app contains a collapsing toolbar with a title. The title is centerend when it is expanded and should stay centered when it is collapsing. With my layout which is below, my device doesn't center the title when it is collapsed, but moves it a little to the right. What do I have to change so it keeps being centered? If it's helpful I can add images as well of course.</p>
  
  <p>My layout:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:ads="http://schemas.android.com/apk/res-auto"
      android:layout_width="match_parent"
      xmlns:app="http://schemas.android.com/apk/res-auto"
      android:background="@android:color/white"
      android:layout_height="match_parent"&gt;
  
      &lt;android.support.design.widget.AppBarLayout
          android:id="@+id/appBar"
          android:layout_width="match_parent"
          android:layout_height="200dp"
          android:fitsSystemWindows="true"
          android:theme="@style/AppTheme.AppBarOverlay"&gt;
  
          &lt;android.support.design.widget.CollapsingToolbarLayout
              android:id="@+id/toolbar_layout"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:fitsSystemWindows="true"
              app:expandedTitleGravity="center|bottom"
              app:title="Test"
              app:collapsedTitleGravity="center"
              app:expandedTitleMarginBottom="56dp"
              app:layout_scrollFlags="scroll|exitUntilCollapsed"
              app:toolbarId="@+id/toolbar"&gt;
  
              &lt;android.support.v7.widget.Toolbar
                  android:id="@+id/toolbar"
                  android:layout_width="match_parent"
                  android:layout_height="?attr/actionBarSize"
                  android:layout_marginBottom="48dp"
                  app:layout_collapseMode="pin"
                  app:popupTheme="@style/AppTheme.PopupOverlay" /&gt;
  
          &lt;/android.support.design.widget.CollapsingToolbarLayout&gt;
      &lt;/android.support.design.widget.AppBarLayout&gt;
  
      &lt;android.support.v4.widget.NestedScrollView
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          android:layout_marginLeft="10dp"
          android:layout_marginRight="10dp"
          android:layout_marginTop="10dp"
          android:fillViewport="true"
          android:layout_gravity="fill_vertical"
          app:layout_behavior="@string/appbar_scrolling_view_behavior"&gt;&gt;
  
      &lt;/android.support.v4.widget.NestedScrollView&gt;
  &lt;/android.support.design.widget.CoordinatorLayout&gt;
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/dZYCI.png" rel="noreferrer">This is what it looks like expanded</a></p>
  
  <p><a href="https://i.stack.imgur.com/NbZnU.png" rel="noreferrer">As you see on this image, it's not centered, but a little moved to the right side</a></p>