Add hints in Overview

If the ENABLE_HINTS_IN_OVERVIEW flag is enabled, pulls chip hint
data (currently from the NavBarHint plugin; eventually from AiAi)
and shows the chips between the task view screenshot and the QSB.

Screenshot: https://screenshot.googleplex.com/Ww05W13XjBv

BUG:124390101

Change-Id: I7686673b705257eca31f2fa40e2744e197153c7c
diff --git a/res/layout/hint_container.xml b/res/layout/hint_container.xml
new file mode 100644
index 0000000..75aa913
--- /dev/null
+++ b/res/layout/hint_container.xml
@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+     Copyright (C) 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.
+-->
+<merge/>
\ No newline at end of file
diff --git a/res/layout/launcher.xml b/res/layout/launcher.xml
index 87078b9..91c3705 100644
--- a/res/layout/launcher.xml
+++ b/res/layout/launcher.xml
@@ -43,6 +43,11 @@
             layout="@layout/overview_panel"
             android:visibility="gone" />
 
+        <include
+            android:id="@+id/hints"
+            layout="@layout/hint_container"
+            android:visibility="gone"/>
+
         <!-- Keep these behind the workspace so that they are not visible when
          we go into AllApps -->
         <com.android.launcher3.pageindicators.WorkspacePageIndicator