Handle auto-pip change in split handling transitions

An auto-pip change might get collected into the transition which has
already claimed by split handler. This makes sure to handle the mixed
transition between split handler and pip handler.

Fix: 285816139
Test: open a fullscreen app on top of a split pair with auto-pip app.
      verified expanding the pip window, split pair is dismissed in
      overview.
Change-Id: I5c723000e7ddc6a96b8992960845400c152ed3d2

libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/StageCoordinator.java

@@ -2453,6 +2453,8 @@ public class StageCoordinator implements SplitLayout.SplitLayoutHandler,
 
             mSplitLayout.setFreezeDividerWindow(false);
             final StageChangeRecord record = new StageChangeRecord();
+            final int transitType = info.getType();
+            boolean hasEnteringPip = false;
             for (int iC = 0; iC < info.getChanges().size(); ++iC) {
                 final TransitionInfo.Change change = info.getChanges().get(iC);
                 if (change.getMode() == TRANSIT_CHANGE
@@ -2460,6 +2462,10 @@ public class StageCoordinator implements SplitLayout.SplitLayoutHandler,
                     mSplitLayout.update(startTransaction);
                 }
 
+                if (mMixedHandler.isEnteringPip(change, transitType)) {
+                    hasEnteringPip = true;
+                }
+
                 final ActivityManager.RunningTaskInfo taskInfo = change.getTaskInfo();
                 if (taskInfo == null) continue;
                 if (taskInfo.token.equals(mRootTaskInfo.token)) {
@@ -2508,6 +2514,13 @@ public class StageCoordinator implements SplitLayout.SplitLayoutHandler,
                     }
                 }
             }
+
+            if (hasEnteringPip) {
+                mMixedHandler.animatePendingEnterPipFromSplit(transition, info,
+                        startTransaction, finishTransaction, finishCallback);
+                return true;
+            }
+
             final ArraySet<StageTaskListener> dismissStages = record.getShouldDismissedStage();
             if (mMainStage.getChildCount() == 0 || mSideStage.getChildCount() == 0
                     || dismissStages.size() == 1) {

libs/WindowManager/Shell/src/com/android/wm/shell/transition/DefaultMixedHandler.java

@@ -42,10 +42,10 @@ import android.window.WindowContainerTransaction;
 import android.window.WindowContainerTransactionCallback;
 
 import com.android.internal.protolog.common.ProtoLog;
+import com.android.wm.shell.common.split.SplitScreenUtils;
 import com.android.wm.shell.desktopmode.DesktopModeController;
 import com.android.wm.shell.desktopmode.DesktopModeStatus;
 import com.android.wm.shell.desktopmode.DesktopTasksController;
-import com.android.wm.shell.common.split.SplitScreenUtils;
 import com.android.wm.shell.keyguard.KeyguardTransitionHandler;
 import com.android.wm.shell.pip.PipTransitionController;
 import com.android.wm.shell.pip.phone.PipTouchHandler;
@@ -470,7 +470,8 @@ public class DefaultMixedHandler implements Transitions.TransitionHandler,
             }
             finishCallback.onTransitionFinished(mixed.mFinishWCT, wctCB);
         };
-        if (isGoingHome) {
+        if (isGoingHome || mSplitHandler.getSplitItemPosition(pipChange.getLastParent())
+                != SPLIT_POSITION_UNDEFINED) {
             ProtoLog.v(ShellProtoLogGroup.WM_SHELL_TRANSITIONS, " Animation is actually mixed "
                     + "since entering-PiP caused us to leave split and return home.");
             // We need to split the transition into 2 parts: the pip part (animated by pip)
@@ -538,11 +539,28 @@ public class DefaultMixedHandler implements Transitions.TransitionHandler,
         return false;
     }
 
+    /**
+     * This is intended to be called by SplitCoordinator as a helper to mix a split handling
+     * transition with an entering-pip change. The use-case for this is when an auto-pip change
+     * gets collected into the transition which has already claimed by
+     * StageCoordinator.handleRequest. This happens when launching a fullscreen app while having an
+     * auto-pip activity in the foreground split pair.
+     */
+    // TODO(b/287704263): Remove when split/mixed are reversed.
+    public boolean animatePendingEnterPipFromSplit(IBinder transition, TransitionInfo info,
+            SurfaceControl.Transaction startT, SurfaceControl.Transaction finishT,
+            Transitions.TransitionFinishCallback finishCallback) {
+        final MixedTransition mixed = new MixedTransition(
+                MixedTransition.TYPE_ENTER_PIP_FROM_SPLIT, transition);
+        mActiveTransitions.add(mixed);
+        return animateEnterPipFromSplit(mixed, info, startT, finishT, finishCallback);
+    }
+
     /**
      * This is intended to be called by SplitCoordinator as a helper to mix an already-pending
      * split transition with a display-change. The use-case for this is when a display
      * change/rotation gets collected into a split-screen enter/exit transition which has already
-     * been claimed by StageCoordinator.handleRequest . This happens during launcher tests.
+     * been claimed by StageCoordinator.handleRequest. This happens during launcher tests.
      */
     public boolean animatePendingSplitWithDisplayChange(@NonNull IBinder transition,
             @NonNull TransitionInfo info, @NonNull SurfaceControl.Transaction startT,
@@ -715,6 +733,13 @@ public class DefaultMixedHandler implements Transitions.TransitionHandler,
         return mPipHandler.requestHasPipEnter(request);
     }
 
+    /** Whether a particular change is a window that is entering pip. */
+    // TODO(b/287704263): Remove when split/mixed are reversed.
+    public boolean isEnteringPip(TransitionInfo.Change change,
+            @WindowManager.TransitionType int transitType) {
+        return mPipHandler.isEnteringPip(change, transitType);
+    }
+
     @Override
     public void mergeAnimation(@NonNull IBinder transition, @NonNull TransitionInfo info,
             @NonNull SurfaceControl.Transaction t, @NonNull IBinder mergeTarget,

libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/splitscreen/SplitTransitionTests.java

@@ -76,6 +76,7 @@ import com.android.wm.shell.common.SyncTransactionQueue;
 import com.android.wm.shell.common.TransactionPool;
 import com.android.wm.shell.common.split.SplitDecorManager;
 import com.android.wm.shell.common.split.SplitLayout;
+import com.android.wm.shell.transition.DefaultMixedHandler;
 import com.android.wm.shell.transition.Transitions;
 import com.android.wm.shell.windowdecor.WindowDecorViewModel;
 
@@ -105,6 +106,7 @@ public class SplitTransitionTests extends ShellTestCase {
     @Mock private WindowDecorViewModel mWindowDecorViewModel;
     @Mock private ShellExecutor mMainExecutor;
     @Mock private LaunchAdjacentController mLaunchAdjacentController;
+    @Mock private DefaultMixedHandler mMixedHandler;
     private SplitLayout mSplitLayout;
     private MainStage mMainStage;
     private SideStage mSideStage;
@@ -136,6 +138,7 @@ public class SplitTransitionTests extends ShellTestCase {
                 mDisplayImeController, mDisplayInsetsController, mSplitLayout, mTransitions,
                 mTransactionPool, mMainExecutor, Optional.empty(),
                 mLaunchAdjacentController, Optional.empty());
+        mStageCoordinator.setMixedHandler(mMixedHandler);
         mSplitScreenTransitions = mStageCoordinator.getSplitTransitions();
         doAnswer((Answer<IBinder>) invocation -> mock(IBinder.class))
                 .when(mTransitions).startTransition(anyInt(), any(), any());