title: White space on top of ViewPager in CoordinatorLayout
body: <p>In the main layout, I have a coordinatorLayout and its children are appbarLayout and viewPager.
  In each page of the viewPager, I have a fragment, that either it has a nestedScrollview or a recyclerview.
  My problem is that there is a white space on top of all the fragments in each page of the viewPager.</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:layout_gravity="fill_vertical"
  android:id="@+id/konta"&gt;
  
  &lt;android.support.design.widget.AppBarLayout
      android:id="@+id/smooth_app_bar_layout"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:background="@color/blue_200"
      android:minHeight="@dimen/mdSecondaryActionBarSize"&gt;
  
      &lt;android.support.design.widget.CollapsingToolbarLayout
          android:id="@+id/collapsing_toolbar_layout"
          android:layout_width="match_parent"
          android:layout_height="@dimen/app_bar_height"
          app:titleEnabled="false"
          app:layout_collapseMode="parallax"
          android:background="@android:color/transparent"
          app:layout_scrollFlags="scroll|snap"&gt;
  
          &lt;android.support.v7.widget.Toolbar
              android:id="@+id/toolbar"
              android:layout_width="match_parent"
              android:layout_height="@dimen/toolbar_height"
              android:background="@android:color/transparent"
              app:layout_collapseMode="pin"
              app:layout_scrollFlags="scroll|enterAlways"
              app:navigationIcon="@drawable/ic_arrow_right" /&gt;
      &lt;/android.support.design.widget.CollapsingToolbarLayout&gt;
      &lt;android.support.design.widget.TabLayout
          android:layoutDirection="ltr"
          tools:targetApi="jelly_bean_mr1"
          android:id="@+id/tab_layout"
          android:layout_width="match_parent"
          android:layout_height="@dimen/tab_size"
          android:background="@android:color/transparent"
          app:tabIndicatorColor="@android:color/white" /&gt;
  
  &lt;/android.support.design.widget.AppBarLayout&gt;
  &lt;android.support.v4.view.ViewPager
      android:id="@+id/view_pager"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:layout_gravity="fill_vertical"
      android:fitsSystemWindows="true"
      app:layout_behavior="@string/appbar_scrolling_view_behavior"/&gt;
  &lt;/android.support.design.widget.CoordinatorLayout&gt;
  </code></pre>