Add empty Taskbar views and initial TaskbarController

Guarded by a FeatureFlag.

Bug: 171917176
Change-Id: I7145c7ae68282bf53552502798fe758c8c0e285d
diff --git a/quickstep/res/layout/taskbar.xml b/quickstep/res/layout/taskbar.xml
new file mode 100644
index 0000000..5f1046d
--- /dev/null
+++ b/quickstep/res/layout/taskbar.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2021 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.
+-->
+
+<com.android.launcher3.taskbar.TaskbarContainerView
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@+id/taskbar_container"
+    android:layout_width="wrap_content"
+    android:layout_height="wrap_content">
+
+    <com.android.launcher3.taskbar.TaskbarView
+        android:id="@+id/taskbar_view"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:background="@color/taskbar_background"/>
+
+</com.android.launcher3.taskbar.TaskbarContainerView>
\ No newline at end of file