Supports the separate display for the input window.

Bug: 136039906
Test: Test manually with the uncommented example config in hawk_md.
Change-Id: I404cc2ce137563ced8e2180dd0539bd98524ff57

samples/MultiClientInputMethod/res/values/config.xml

@@ -0,0 +1,35 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+/*
+** Copyright 2019, 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.
+*/
+-->
+<resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+  <string-array name="config_inputDisplayToImeDisplay">
+  <!--
+    The MultiClientInputMethod will use the same display for the IME window by default.
+    But, if you want to use the separate display for the IME window, consider to define item of
+    'config_inputDisplayToImeDisplay'.  The each item is a comma-separated pair of the uniqueId of
+    the displays.  The first is the uniqueId of the display where the input happens and the second
+    is the unqiueId of the display where the IME window will be shown.
+    FYI, you can find the uniqueId of displays in "dumpsys display".
+
+    E.g. If you have two displays 19261083906282752, local:19260422155234049 and you want to use
+    local:19260422155234049 as the IME window for the input at the display local:19261083906282752,
+    then the config item will be:
+      <item>local:19261083906282752,local:19260422155234049</item>
+  -->
+  </string-array>
+</resources>