Use Material theme's default enabling of Activity Transitions.

Bug 15746767

Change-Id: I88eaeeab5483cc2b82837a2ddca6702ffa25fcd4
diff --git a/samples/ApiDemos/res/values/styles.xml b/samples/ApiDemos/res/values/styles.xml
index bf36ea4..0fa0cc1 100644
--- a/samples/ApiDemos/res/values/styles.xml
+++ b/samples/ApiDemos/res/values/styles.xml
@@ -127,7 +127,6 @@
 	<item name="android:windowSharedElementExitTransition">@transition/move_image</item>
 	<item name="android:windowAllowExitTransitionOverlap">true</item>
 	<item name="android:windowAllowEnterTransitionOverlap">false</item>
-        <item name="android:windowContentTransitions">true</item>
     </style>
 
 </resources>