title: Toolbar default style and Navigation Icon
body: <p>I have a <code>Toolbar</code> inside an <code>AppBarLayout</code>.
  Here is the XML of both views : </p>
  
  <pre><code>&lt;android.support.design.widget.AppBarLayout
      android:id="@+id/appbarlayout"
      android:layout_height="wrap_content"
      android:layout_width="match_parent"
      android:theme="@style/App.ThemeOverlay.Toolbar"&gt;
  
      &lt;android.support.v7.widget.Toolbar
          android:id="@+id/toolbar"
          android:layout_height="?attr/actionBarSize"
          android:layout_width="match_parent"/&gt;
  
  &lt;/android.support.design.widget.AppBarLayout&gt;
  </code></pre>
  
  <p>With the theme : </p>
  
  <pre><code>&lt;style name="App.ThemeOverlay.Toolbar" parent="ThemeOverlay.AppCompat.Dark.ActionBar"/&gt;
  </code></pre>
  
  <p>And the Theme applied to the <code>Activity</code> :</p>
  
  <pre><code>&lt;style name="App.Theme" parent="Theme.AppCompat.Light.NoActionBar"&gt;
      &lt;item name="colorPrimary"&gt;@color/colorPrimary&lt;/item&gt;
      &lt;item name="colorPrimaryDark"&gt;@color/colorPrimaryDark&lt;/item&gt;
      &lt;item name="colorAccent"&gt;@color/colorAccent&lt;/item&gt;
      &lt;item name="android:windowBackground"&gt;@android:color/white&lt;/item&gt;
  &lt;/style&gt;
  </code></pre>
  
  <p>Now, I want to apply a custom <code>titleTextAppearance</code> for the toolbar.</p>
  
  <p>I know that I can use <code>app:titleTextAppearance</code> in my layout's XML but I want to configure it from the theme so that every Toolbar of my app will have the same style without setting the text appearance in every layout.</p>
  
  <p>After a bit of digging in AppCompat source code, I found that <code>Toolbar</code> uses the <code>toolbarStyle</code> of the current theme as its default theme. </p>
  
  <p>The default value of this style is <code>Widget.AppCompat.ActionBar</code>.</p>
  
  <p>So my first guess is to override this style in my theme overlay, and change the <code>titleTextAppearance</code> in this new style :</p>
  
  <pre><code>&lt;style name="App.ThemeOverlay.Toolbar" parent="ThemeOverlay.AppCompat.Dark.ActionBar"&gt;
      &lt;item name="toolbarStyle"&gt;@style/App.Style.Toolbar&lt;/item&gt;    
  &lt;/style&gt;
  
  &lt;style name="App.Style.Toolbar" parent="Widget.AppCompat.ActionBar"&gt;
      &lt;item name="titleTextAppearance"&gt;@style/App.TextAppearance.Toolbar.Title&lt;/item&gt;
  &lt;/style&gt;
  
  &lt;style name="App.TextAppearance.Toolbar.Title" parent="TextAppearance.Widget.AppCompat.Toolbar.Title"&gt;
      &lt;item name="android:textColor"&gt;#00FF00&lt;/item&gt; (this is some green)
      &lt;item name="android:textAllCaps"&gt;true&lt;/item&gt;
  &lt;/style&gt;
  </code></pre>
  
  <p>This actually overrides the <code>titleTextAppearance</code> of my toolbar but it's also breaking the navigation icon :</p>
  
  <p><a href="https://i.stack.imgur.com/CDwsC.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/CDwsC.jpg" alt="Toolbar Style Fail"></a></p>
  
  <p>What is wrong with my configuration that breaks the navigation icon ?</p>
  
  <p>For the record, I tried to remove the <code>toolbarStyle</code> of the theme overlay and used directly in the layout's XML of the toolbar <code>style="@style/App.Style.Toolbar"</code>.</p>
  
  <p>This correctly applies the title text appearance and it's not breaking the navigation icon, but this is not optimal as I would have to apply the style to every toolbar of my app, and that's what I'm trying to avoid from the beginning.</p>
  
  <p>Thanks for the helps,
  Pierre</p>