Add conversation onboarding

Test: atest
Fixes: 150791002
Change-Id: I51c27300acb8e18b28b5b5e5bf0d2623c65af909

res/layout/conversation_onboarding.xml

@@ -0,0 +1,43 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+              android:layout_width="match_parent"
+              android:layout_height="match_parent"
+              android:layout_gravity="center"
+              android:gravity="center"
+              android:orientation="vertical">
+
+    <ImageView
+        android:layout_width="80dp"
+        android:layout_height="80dp"
+        android:layout_marginTop="143dp"
+        android:src="@drawable/ic_promote_conversation"/>
+    <TextView
+        android:layout_width="316dp"
+        android:layout_height="wrap_content"
+        android:gravity="center"
+        android:textAppearance="?android:attr/textAppearanceMedium"
+        android:textColor="?android:attr/textColorSecondary"
+        android:layout_marginTop="47dp"
+        android:text="@string/conversation_onboarding_title"/>
+    <TextView
+        android:layout_width="316dp"
+        android:layout_height="wrap_content"
+        android:gravity="center"
+        android:layout_marginTop="24dp"
+        android:text="@string/conversation_onboarding_summary"/>
+</LinearLayout>