Don't dispatch onBackCancelled if start is not dispatched.

Bug: 329491664
Fixes: 329491664
Test: long press on the edge of all-apps (built from SysUI-Studio). Make
sure there's no crashes.
Test: atest BackAnimationControllerTest

Change-Id: I0d28373b3341e6637dfaf0adaf7b3ddf0196f69b

2 files changed, 25 insertions, 4 deletions

diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/back/BackAnimationController.java b/libs/WindowManager/Shell/src/com/android/wm/shell/back/BackAnimationController.java
index 9bd8531d33dc..78129c281fce 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/back/BackAnimationController.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/back/BackAnimationController.java
@@ -670,7 +670,11 @@ public class BackAnimationController implements RemoteCallable<BackAnimationCont
         }
     }
 
-    private void dispatchOnBackCancelled(IOnBackInvokedCallback callback) {
+    private void tryDispatchOnBackCancelled(IOnBackInvokedCallback callback) {
+        if (!mOnBackStartDispatched) {
+            Log.e(TAG, "Skipping dispatching onBackCancelled. Start was never dispatched.");
+            return;
+        }
         if (callback == null) {
             return;
         }
@@ -729,7 +733,7 @@ public class BackAnimationController implements RemoteCallable<BackAnimationCont
             if (touchTracker.getTriggerBack()) {
                 dispatchOrAnimateOnBackInvoked(callback, touchTracker);
             } else {
-                dispatchOnBackCancelled(callback);
+                tryDispatchOnBackCancelled(callback);
             }
         }
         finishBackNavigation(touchTracker.getTriggerBack());
@@ -808,7 +812,7 @@ public class BackAnimationController implements RemoteCallable<BackAnimationCont
         if (mCurrentTracker.getTriggerBack()) {
             dispatchOrAnimateOnBackInvoked(mActiveCallback, mCurrentTracker);
         } else {
-            dispatchOnBackCancelled(mActiveCallback);
+            tryDispatchOnBackCancelled(mActiveCallback);
         }
     }
 
@@ -846,7 +850,7 @@ public class BackAnimationController implements RemoteCallable<BackAnimationCont
         if (mCurrentTracker.isInInitialState()) {
             if (mBackGestureStarted) {
                 mBackGestureStarted = false;
-                dispatchOnBackCancelled(mActiveCallback);
+                tryDispatchOnBackCancelled(mActiveCallback);
                 finishBackNavigation(false);
                 ProtoLog.d(WM_SHELL_BACK_PREVIEW,
                         "resetTouchTracker -> reset an unfinished gesture");
diff --git a/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/back/BackAnimationControllerTest.java b/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/back/BackAnimationControllerTest.java
index 9ded6ea1d187..0d3f00d37801 100644
--- a/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/back/BackAnimationControllerTest.java
+++ b/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/back/BackAnimationControllerTest.java
@@ -527,6 +527,23 @@ public class BackAnimationControllerTest extends ShellTestCase {
     }
 
     @Test
+    public void skipsCancelWithoutStart() throws RemoteException {
+        final int type = BackNavigationInfo.TYPE_CALLBACK;
+        final ResultListener result = new ResultListener();
+        createNavigationInfo(new BackNavigationInfo.Builder()
+                .setType(type)
+                .setOnBackInvokedCallback(mAppCallback)
+                .setOnBackNavigationDone(new RemoteCallback(result)));
+        doMotionEvent(MotionEvent.ACTION_CANCEL, 0);
+        mShellExecutor.flushAll();
+
+        verify(mAppCallback, never()).onBackStarted(any());
+        verify(mAppCallback, never()).onBackProgressed(any());
+        verify(mAppCallback, never()).onBackInvoked();
+        verify(mAppCallback, never()).onBackCancelled();
+    }
+
+    @Test
     public void testBackToActivity() throws RemoteException {
         final CrossActivityBackAnimation animation = new CrossActivityBackAnimation(mContext,
                 mAnimationBackground);