Hide actionbar title text in activity preview

Bug: 14258061
Change-Id: Icb016476162362adf2476f3cba05672aa4f12a18
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index e36c834..7795aa8 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -68,7 +68,7 @@
              dialpad screen. -->
         <activity android:name=".DialtactsActivity"
             android:label="@string/launcherDialer"
-            android:theme="@style/DialtactsTheme"
+            android:theme="@style/DialtactsActivityTheme"
             android:launchMode="singleTask"
             android:clearTaskOnLaunch="true"
             android:icon="@mipmap/ic_launcher_phone"
diff --git a/res/values/styles.xml b/res/values/styles.xml
index 381ee35..a4d9b4e 100644
--- a/res/values/styles.xml
+++ b/res/values/styles.xml
@@ -89,6 +89,11 @@
         <item name="android:windowActionBarOverlay">false</item>
     </style>
 
+    <!-- Hide the actionbar title during the activity preview -->
+    <style name="DialtactsActivityTheme" parent="DialtactsTheme">
+        <item name="android:actionBarStyle">@style/DialtactsActionBarWithoutTitleStyle</item>
+    </style>
+
     <style name="CallDetailActivityTheme" parent="android:Theme.Quantum.Light">
         <item name="android:windowBackground">@color/background_dialer_light</item>
         <item name="android:gravity">top</item>
@@ -158,6 +163,10 @@
         <item name="android:icon">@android:color/transparent</item>
     </style>
 
+    <style name="DialtactsActionBarWithoutTitleStyle" parent="DialtactsActionBarStyle">
+        <item name="android:displayOptions"></item>
+    </style>
+
     <!-- Text in the action bar at the top of the screen -->
     <style name="DialtactsActionBarTitleText"
            parent="@android:style/TextAppearance.Quantum.Widget.ActionBar.Title">