Fix race when rotating the display during an entry into PIP

Rotating the display while the PIP task had just appeared caused
a race between the alpha entry animation starting and the rotation
controller handling that changes the PIP bounds, resulting in
a bounds mismatch between the surface that was animated and the
PipBoundsState.mBounds

This CL tracks whether we're still waiting for the alpha entry
animation to start when a rotation callback comes in, and
restarts the fade in after adjusting to the rotation.

Bug: 184664409
Test: In gesure nav, open YT go to fullscreen landscape mode and
launch another an activity from a notification - verify PIP fades
in and its bounds match the ones in PipBoundsState

Change-Id: I339d5088fb5f23f08fe8d548b9d02a34c16779d6

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

@@ -37,6 +37,7 @@ import com.android.wm.shell.animation.Interpolators;
 
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
+import java.util.Objects;
 
 /**
  * Controller class of PiP animations (both from and to PiP mode).
@@ -112,6 +113,7 @@ public class PipAnimationController {
                     PipTransitionAnimator.ofAlpha(taskInfo, leash, destinationBounds, alphaStart,
                             alphaEnd));
         } else if (mCurrentAnimator.getAnimationType() == ANIM_TYPE_ALPHA
+                && Objects.equals(destinationBounds, mCurrentAnimator.getDestinationBounds())
                 && mCurrentAnimator.isRunning()) {
             mCurrentAnimator.updateEndValue(alphaEnd);
         } else {

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

@@ -98,9 +98,10 @@ public class PipTaskOrganizer implements ShellTaskOrganizer.TaskListener,
     private enum State {
         UNDEFINED(0),
         TASK_APPEARED(1),
-        ENTERING_PIP(2),
-        ENTERED_PIP(3),
-        EXITING_PIP(4);
+        ENTRY_SCHEDULED(2),
+        ENTERING_PIP(3),
+        ENTERED_PIP(4),
+        EXITING_PIP(5);
 
         private final int mStateValue;
 
@@ -263,6 +264,13 @@ public class PipTaskOrganizer implements ShellTaskOrganizer.TaskListener,
         return mState.isInPip() && mWaitForFixedRotation;
     }
 
+    /**
+     * Returns whether the entry animation is waiting to be started.
+     */
+    public boolean isEntryScheduled() {
+        return mState == State.ENTRY_SCHEDULED;
+    }
+
     /**
      * Registers a callback when a display change has been detected when we enter PiP.
      */
@@ -481,6 +489,19 @@ public class PipTaskOrganizer implements ShellTaskOrganizer.TaskListener,
         }
     }
 
+    /**
+     * Called when the display rotation handling is skipped (e.g. when rotation happens while in
+     * the middle of an entry transition).
+     */
+    public void onDisplayRotationSkipped() {
+        if (isEntryScheduled()) {
+            // The PIP animation is scheduled to start with the previous orientation's bounds,
+            // re-calculate the entry bounds and restart the alpha animation.
+            final Rect destinationBounds = mPipBoundsAlgorithm.getEntryDestinationBounds();
+            enterPipWithAlphaAnimation(destinationBounds, mEnterAnimationDuration);
+        }
+    }
+
     @VisibleForTesting
     void enterPipWithAlphaAnimation(Rect destinationBounds, long durationMs) {
         // If we are fading the PIP in, then we should move the pip to the final location as
@@ -490,6 +511,7 @@ public class PipTaskOrganizer implements ShellTaskOrganizer.TaskListener,
                 mSurfaceControlTransactionFactory.getTransaction();
         tx.setAlpha(mLeash, 0f);
         tx.apply();
+        mState = State.ENTRY_SCHEDULED;
         applyEnterPipSyncTransaction(destinationBounds, () -> {
             mPipAnimationController
                     .getAnimator(mTaskInfo, mLeash, destinationBounds, 0f, 1f)

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

@@ -115,7 +115,8 @@ public class PipController implements PipTransitionController.PipTransitionCallb
             int displayId, int fromRotation, int toRotation, WindowContainerTransaction t) -> {
         if (!mPipTaskOrganizer.isInPip()
                 || mPipBoundsState.getDisplayLayout().rotation() == toRotation
-                || mPipTaskOrganizer.isDeferringEnterPipAnimation()) {
+                || mPipTaskOrganizer.isDeferringEnterPipAnimation()
+                || mPipTaskOrganizer.isEntryScheduled()) {
             // Skip if the same rotation has been set or we aren't in PIP or haven't actually
             // entered PIP yet. We still need to update the display layout in the bounds handler
             // in this case.
@@ -123,6 +124,7 @@ public class PipController implements PipTransitionController.PipTransitionCallb
             // do not forget to update the movement bounds as well.
             updateMovementBounds(mPipBoundsState.getNormalBounds(), true /* fromRotation */,
                     false /* fromImeAdjustment */, false /* fromShelfAdjustment */, t);
+            mPipTaskOrganizer.onDisplayRotationSkipped();
             return;
         }
         // If there is an animation running (ie. from a shelf offset), then ensure that we calculate