Fix document mode promo ImageView height.

chrome/android/java/res/layout/opt_out_promo.xml

 <?xml version="1.0" encoding="utf-8"?>
 <!-- Copyright 2015 The Chromium Authors. All rights reserved.
      Use of this source code is governed by a BSD-style license that can be
      found in the LICENSE file. -->
 
 <LinearLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:id="@+id/opt_out_promo"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
     android:orientation="vertical">
 
     <ImageView
         android:id="@+id/tabs_moved_illustration"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:gravity="center"
+        android:adjustViewBounds="true"
         android:background="#4FC3F7"
         android:contentDescription="@null" />
 
     <TextView
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:textSize="16sp"
         android:layout_marginTop="24dp"
         android:layout_marginStart="32dp"
         android:layout_marginEnd="32dp"
@@ skipping 17 matching lines @@
         android:id="@+id/got_it_button"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_gravity="end"
         android:layout_marginTop="24dp"
         android:layout_marginBottom="16dp"
         android:layout_marginEnd="32dp"
         android:text="@string/tabs_and_apps_got_it_button"
         android:textColor="@color/light_active_color" />
 </LinearLayout>