PiP: Fix more Shell Transition potential issues.

If an animator is already running, we usually just update its end
bounds - but we also end up over-writing the original callbacks. This
used to work well since pre-shell transition, callbacks are always
pulled from PipTaskOrganizer, but now we can have two places that supply
callbacks (PipTransition). So let's just leave the callback alone.

Another potential issue is that sometimes finish callbacks from one
transition is not called before starting another one, and starting a new
transition overwrites the old finishCallback. We will then finish the
earlier callbacks to ensure the transition system does not hang the
entire device, but throw an Exception to not gloss over the potential
issue.

Bug: 183993924
Test: atest PinnedStackTests
Change-Id: Ib4c5926beec5745d8a0abccec5c67849488e532b

libs/WindowManager/Shell/src/com/android/wm/shell/pip/PipTaskOrganizer.java

@@ -1292,13 +1292,17 @@ public class PipTaskOrganizer implements ShellTaskOrganizer.TaskListener,
         }
         Rect baseBounds = direction == TRANSITION_DIRECTION_SNAP_AFTER_RESIZE
                 ? mPipBoundsState.getBounds() : currentBounds;
+        final boolean existingAnimatorRunning = mPipAnimationController.getCurrentAnimator() != null
+                && mPipAnimationController.getCurrentAnimator().isRunning();
         final PipAnimationController.PipTransitionAnimator<?> animator = mPipAnimationController
                 .getAnimator(mTaskInfo, mLeash, baseBounds, currentBounds, destinationBounds,
                         sourceHintRect, direction, startingAngle, rotationDelta);
         animator.setTransitionDirection(direction)
-                .setPipAnimationCallback(mPipAnimationCallback)
                 .setPipTransactionHandler(mPipTransactionHandler)
                 .setDuration(durationMs);
+        if (!existingAnimatorRunning) {
+            animator.setPipAnimationCallback(mPipAnimationCallback);
+        }
         if (isInPipDirection(direction)) {
             // Similar to auto-enter-pip transition, we use content overlay when there is no
             // source rect hint to enter PiP use bounds animation.

libs/WindowManager/Shell/src/com/android/wm/shell/pip/PipTransition.java

@@ -116,6 +116,12 @@ public class PipTransition extends PipTransitionController {
         if (mExitTransition == transition || info.getType() == TRANSIT_EXIT_PIP) {
             mExitTransition = null;
             if (info.getChanges().size() == 1) {
+                if (mFinishCallback != null) {
+                    mFinishCallback.onTransitionFinished(null, null);
+                    mFinishCallback = null;
+                    throw new RuntimeException("Previous callback not called, aborting exit PIP.");
+                }
+
                 final TransitionInfo.Change change = info.getChanges().get(0);
                 mFinishCallback = finishCallback;
                 startTransaction.apply();
@@ -129,6 +135,12 @@ public class PipTransition extends PipTransitionController {
         }
 
         if (info.getType() == TRANSIT_REMOVE_PIP) {
+            if (mFinishCallback != null) {
+                mFinishCallback.onTransitionFinished(null /* wct */, null /* callback */);
+                mFinishCallback = null;
+                throw new RuntimeException("Previous callback not called, aborting remove PIP.");
+            }
+
             startTransaction.apply();
             finishTransaction.setWindowCrop(info.getChanges().get(0).getLeash(),
                     mPipBoundsState.getDisplayBounds());
@@ -159,6 +171,12 @@ public class PipTransition extends PipTransitionController {
             return false;
         }
 
+        if (mFinishCallback != null) {
+            mFinishCallback.onTransitionFinished(null /* wct */, null /* callback */);
+            mFinishCallback = null;
+            throw new RuntimeException("Previous callback not called, aborting entering PIP.");
+        }
+
         // Show the wallpaper if there is a wallpaper change.
         if (wallpaper != null) {
             startTransaction.show(wallpaper.getLeash());
@@ -231,7 +249,7 @@ public class PipTransition extends PipTransitionController {
             if (tx != null) {
                 wct.setBoundsChangeTransaction(taskInfo.token, tx);
             }
-            mFinishCallback.onTransitionFinished(wct, null /* wctCallback */);
+            mFinishCallback.onTransitionFinished(wct, null /* callback */);
             mFinishCallback = null;
         }
         finishResizeForMenu(destinationBounds);
@@ -240,7 +258,7 @@ public class PipTransition extends PipTransitionController {
     @Override
     public void forceFinishTransition() {
         if (mFinishCallback == null) return;
-        mFinishCallback.onTransitionFinished(null /* wct */, null /* wctCallback */);
+        mFinishCallback.onTransitionFinished(null /* wct */, null /* callback */);
         mFinishCallback = null;
     }
 
@@ -286,7 +304,6 @@ public class PipTransition extends PipTransitionController {
             mPipBoundsState.setBounds(destinationBounds);
             onFinishResize(taskInfo, destinationBounds, TRANSITION_DIRECTION_TO_PIP, null /* tx */);
             sendOnPipTransitionFinished(TRANSITION_DIRECTION_TO_PIP);
-            mFinishCallback = null;
             mPipTransitionState.setInSwipePipToHomeTransition(false);
             return true;
         }