Set keyboard pages background to white

app/src/main/res/layout/emoji_popup_layout.xml

@@ -2,19 +2,20 @@
 <android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
     android:id="@+id/emoji_keyboard_container"
-    android:visibility="gone"
     android:layout_width="match_parent"
-    android:layout_height="200dp">
+    android:layout_height="200dp"
+    android:background="@color/white"
+    android:visibility="gone">
 
     <View
         android:id="@+id/divider"
         android:layout_width="match_parent"
         android:layout_height="1dp"
         android:background="@color/colorDividerMessageComposer"
-        app:layout_constraintTop_toTopOf="parent"
+        app:layout_constraintBottom_toTopOf="@+id/tabs"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent"
-        app:layout_constraintBottom_toTopOf="@+id/tabs" />
+        app:layout_constraintTop_toTopOf="parent" />
 
     <android.support.design.widget.TabLayout
         android:id="@+id/tabs"