General cleanup on AppRTC Android Demo codebase

webrtc/examples/androidapp/res/layout/activity_call.xml

 <?xml version="1.0" encoding="utf-8"?>
 
 <RelativeLayout
-        xmlns:android="http://schemas.android.com/apk/res/android"
-        xmlns:tools="http://schemas.android.com/tools"
-        android:layout_width="match_parent"
-        android:layout_height="match_parent">
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
 
     <org.appspot.apprtc.PercentFrameLayout
         android:id="@+id/remote_video_layout"
         android:layout_width="match_parent"
         android:layout_height="match_parent">
         <org.webrtc.SurfaceViewRenderer
             android:id="@+id/remote_video_view"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content" />
     </org.appspot.apprtc.PercentFrameLayout>
@@ skipping 11 matching lines @@
     <FrameLayout
         android:id="@+id/call_fragment_container"
         android:layout_width="match_parent"
         android:layout_height="match_parent" />
     <FrameLayout
         android:id="@+id/hud_fragment_container"
         android:layout_width="match_parent"
         android:layout_height="match_parent" />
 
 </RelativeLayout>