Add support for Android spellcheck menu in Chrome/WebViews

content/public/android/java/res/layout-v21/text_edit_suggestion_container.xml

Index: content/public/android/java/res/layout-v21/text_edit_suggestion_container.xml
diff --git a/content/public/android/java/res/layout-v21/text_edit_suggestion_container.xml b/content/public/android/java/res/layout-v21/text_edit_suggestion_container.xml
new file mode 100644
index 0000000000000000000000000000000000000000..36cc8278d626d0050b2203abce3ac82c00739434
--- /dev/null
+++ b/content/public/android/java/res/layout-v21/text_edit_suggestion_container.xml
@@ -0,0 +1,25 @@
+<?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. -->
+
+<!-- Based on Android's text_edit_suggestion_container_material.xml -->
+<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="wrap_content"
+    android:layout_height="wrap_content">
+    <!-- On Lollipop and later (this file), we draw a drop shadow using elevation.
+         On pre-Lollipop, we instead draw the drop shadow using
+         @drawable/dropdown_popup_background. -->
+    <LinearLayout
+        style="@style/TextSuggestionWindowContainer"
+        android:id="@+id/suggestionWindowContainer"
+        android:background="@drawable/floating_popup_background_light"
+        android:elevation="2dp"
+        tools:ignore="UselessParent">

[Theresa, 2017/07/18 15:37:51]

Can you please try removing ReleativeLayout instead of suppressing the
"UselessParent" warning?

[rlanday, 2017/07/19 00:23:55]

Ok, I experimented a bit and found a way to do this. I was also able to get rid
of the margin you didn't like (I still have it as a dimension so we can keep the
menu from appearing too close to the top/bottom of the window, to match the
existing Android menu's behavior).

This lets us consolidate mContentView and mContainerView.

+        <ListView
+            android:id="@+id/suggestionContainer"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content" />
+    </LinearLayout>
+</RelativeLayout>