title: collapsing actionbar not working
body: <p>I'd like to collaps the actionbar, as chrome does, but it's not working:</p>
  
  <p>This is my activity_main.xml file:</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:app="http://schemas.android.com/apk/res-auto"
      xmlns:tools="http://schemas.android.com/tools"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:fitsSystemWindows="true"
      tools:context="com.moover.moover.MainActivity"&gt;
  
      &lt;android.support.design.widget.AppBarLayout
          android:id="@+id/app_bar_layout"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:theme="@style/AppTheme.AppBarOverlay"&gt;
  
          &lt;android.support.design.widget.CollapsingToolbarLayout
              android:id="@+id/collapsing_toolbar"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              app:layout_scrollFlags="scroll|exitUntilCollapsed"
              app:contentScrim="?attr/colorPrimary"&gt;
              &lt;android.support.v7.widget.Toolbar
                  android:id="@+id/toolbar"
                  android:layout_width="match_parent"
                  android:layout_height="?attr/actionBarSize"
                  android:background="?attr/colorPrimary"
                  app:popupTheme="@style/AppTheme.PopupOverlay"
                  app:layout_collapseMode="pin" /&gt;
          &lt;/android.support.design.widget.CollapsingToolbarLayout&gt;
  
          &lt;android.support.v7.widget.Toolbar
              android:id="@+id/toolbar2"
              android:layout_width="match_parent"
              android:layout_height="?attr/actionBarSize"
              android:background="?attr/colorPrimary"
              app:popupTheme="@style/AppTheme.PopupOverlay"&gt;
              &lt;LinearLayout
                  android:layout_width="wrap_content"
                  android:layout_height="wrap_content"&gt;
                  &lt;TextView
                      android:gravity="center_vertical"
                      android:textSize="15dp"
                      android:id="@+id/textViewWebPage"
                      android:layout_width="wrap_content"
                      android:layout_height="wrap_content"
                      android:textColor="@color/secondToolbarTextColor"
                      /&gt;
                  &lt;TextView
                      android:gravity="bottom"
                      android:textSize="15dp"
                      android:id="@+id/textViewTitle"
                      android:layout_width="wrap_content"
                      android:layout_height="wrap_content"
                      android:textColor="@color/secondToolbarTextColor"
                      /&gt;
  
              &lt;/LinearLayout&gt;
  
          &lt;/android.support.v7.widget.Toolbar&gt;
  
      &lt;/android.support.design.widget.AppBarLayout&gt;
  
      &lt;include layout="@layout/content_main" /&gt;
  
  &lt;/android.support.design.widget.CoordinatorLayout&gt;
  </code></pre>
  
  <p>So basically I need to collaps the action bar. I added the collapsing layout but it's not working</p>