Fix overdraw in PeopleActivity

Remove window background in onCreate. Add and remove various view
backgrounds to reduce overdraw.

Bug: 7267295
Change-Id: I868f194f2e91be1011268faa454dfd1278510b8b
diff --git a/res/layout/people_activity.xml b/res/layout/people_activity.xml
index 589e4a9..8ad36ba 100644
--- a/res/layout/people_activity.xml
+++ b/res/layout/people_activity.xml
@@ -17,7 +17,8 @@
 <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:id="@+id/list_container"
     android:layout_width="match_parent"
-    android:layout_height="match_parent">
+    android:layout_height="match_parent"
+    android:background="@color/background_primary">
 
     <!--
         ViewPager for swiping between tabs.  We put StrequentContactListFragment,