Updating gesture tutorial home animation

> Using a separate View as icon, instead of the taskView
> Updating swipe animation logic to abstract out FloatingIconView dependency

Change-Id: Ib466262afead11ebe4ca035d589f0382c37e3e97
diff --git a/quickstep/res/drawable/bg_circle.xml b/quickstep/res/drawable/bg_circle.xml
new file mode 100644
index 0000000..506177b
--- /dev/null
+++ b/quickstep/res/drawable/bg_circle.xml
@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+    Copyright (C) 2020 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.
+-->
+<shape xmlns:android="http://schemas.android.com/apk/res/android"
+    android:shape="oval">
+    <solid android:color="#FFFFFFFF" />
+</shape>
\ No newline at end of file