put toolbar elevation in dimen file

src/main/res/layout/activity_start_conversation.xml

@@ -13,7 +13,7 @@
             android:layout_height="wrap_content"
             android:background="?attr/colorPrimary"
             android:minHeight="?attr/actionBarSize"
-            android:elevation="6dp"
+            android:elevation="@dimen/toolbar_elevation"
             app:tabMode="fixed"
             app:tabGravity="fill"
             app:tabTextColor="@color/white70"

src/main/res/layout/toolbar.xml

@@ -4,7 +4,7 @@
     android:layout_height="wrap_content"
     android:background="?attr/colorPrimary"
     android:minHeight="?attr/actionBarSize"
-    android:elevation="4dp"
+    android:elevation="@dimen/toolbar_elevation"
     android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
     app:popupTheme="?popupOverlayStyle"
     xmlns:android="http://schemas.android.com/apk/res/android"

src/main/res/values/dimens.xml

@@ -12,6 +12,8 @@
 	<dimen name="swipe_handle_size">32dp</dimen>
 	<dimen name="avatar_item_distance">16dp</dimen>
 
+	<dimen name="toolbar_elevation">4dp</dimen>
+
 	<dimen name="publish_avatar_top_margin">8dp</dimen>
 	<dimen name="publish_avatar_size">96dp</dimen>