Expose method to clear all visible recent tasks

- Atomically remove all the visible tasks so that SysUI doesn't need to
  remove each task individually.

Bug: 80471073
Test: atest FrameworksServicesTests:RecentTasksTest#testRemoveAllVisibleTasks
Change-Id: I23a6e152e94d5462948ab40adc9d7baf593847e1
diff --git a/services/core/java/com/android/server/am/ActivityTaskManagerService.java b/services/core/java/com/android/server/am/ActivityTaskManagerService.java
index 3b3263c..8ab4a37 100644
--- a/services/core/java/com/android/server/am/ActivityTaskManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityTaskManagerService.java
@@ -1668,6 +1668,19 @@
     }
 
     @Override
+    public void removeAllVisibleRecentTasks() {
+        enforceCallerIsRecentsOrHasPermission(REMOVE_TASKS, "removeAllVisibleRecentTasks()");
+        synchronized (mGlobalLock) {
+            final long ident = Binder.clearCallingIdentity();
+            try {
+                getRecentTasks().removeAllVisibleTasks();
+            } finally {
+                Binder.restoreCallingIdentity(ident);
+            }
+        }
+    }
+
+    @Override
     public boolean shouldUpRecreateTask(IBinder token, String destAffinity) {
         synchronized (mGlobalLock) {
             final ActivityRecord srec = ActivityRecord.forTokenLocked(token);