[Android] Add android:roundIcon for adaptive icon support

BUG=707449

Review-Url: https://codereview.chromium.org/2850253003
Cr-Commit-Position: refs/heads/master@{#468410}

chrome/android/java/AndroidManifest.xml

@@ -110,6 +110,7 @@ by a child template that "extends" this file.
          Java heap limit (32Mb on Nexus S, 48Mb on Xoom). -->
     <application android:name="{% block application_name %}org.chromium.chrome.browser.ChromeApplication{% endblock %}"
         android:icon="@drawable/ic_launcher"
+        android:roundIcon="@drawable/ic_launcher_round"
         android:label="@string/app_name"
         android:largeHeap="false"
         android:manageSpaceActivity="@string/manage_space_activity"

chrome/android/java/res/values/ic_launcher_round_alias.xml

+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright 2017 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. -->
+
+<resources>
+    <drawable name="ic_launcher_round">@mipmap/app_icon</drawable>
+</resources>