Change taskbar corner roundness when entering overview

- Roundness will be 0 in Launcher, and 1 in an app

Bug: 250645563
Test: With and without taskbar in overview, switch between home/overview/app and observe the round corners above taskbar
Test: Ensure corner above taskbar is correct in overview and in app when chat bubble is active
Change-Id: I1f4911626c8e79fce8d81a76a9bd0d0670d111da

quickstep/src/com/android/launcher3/taskbar/TaskbarScrimViewController.java

@@ -30,7 +30,8 @@ import java.io.PrintWriter;
 /**
  * Handles properties/data collection, and passes the results to {@link TaskbarScrimView} to render.
  */
-public class TaskbarScrimViewController implements TaskbarControllers.LoggableTaskbarController {
+public class TaskbarScrimViewController implements TaskbarControllers.LoggableTaskbarController,
+        TaskbarControllers.BackgroundRendererController {
 
     private static final float SCRIM_ALPHA = 0.6f;
 
@@ -94,6 +95,11 @@ public class TaskbarScrimViewController implements TaskbarControllers.LoggableTa
         SystemUiProxy.INSTANCE.get(mActivity).onBackPressed();
     }
 
+    @Override
+    public void setCornerRoundness(float cornerRoundness) {
+        mScrimView.setCornerRoundness(cornerRoundness);
+    }
+
     @Override
     public void dumpLogs(String prefix, PrintWriter pw) {
         pw.println(prefix + "TaskbarScrimViewController:");