Make sure callback is only called once

Because we set it already in the future, it was called already
when we fetched the contents of the future, because it looked
like we overrided the callback. Instead, don't do callbacks
when calling the future, and save the callback in a separate
field.

Bug: 25568693
Change-Id: I8b7fd4248a2336470f8b7e12b64b0577dee96f6f

services/core/java/com/android/server/wm/AppTransition.java

@@ -164,6 +164,7 @@ public class AppTransition implements Dump {
     // Used for thumbnail transitions. True if we're scaling up, false if scaling down
     private boolean mNextAppTransitionScaleUp;
     private IRemoteCallback mNextAppTransitionCallback;
+    private IRemoteCallback mNextAppTransitionFutureCallback;
     private IRemoteCallback mAnimationFinishedCallback;
     private int mNextAppTransitionEnter;
     private int mNextAppTransitionExit;
@@ -1448,10 +1449,7 @@ public class AppTransition implements Dump {
             mNextAppTransitionAnimationsSpecs.clear();
             mNextAppTransitionAnimationsSpecsFuture = specsFuture;
             mNextAppTransitionScaleUp = scaleUp;
-            postAnimationCallback();
-            mNextAppTransitionCallback = callback;
-        } else {
-            postAnimationCallback();
+            mNextAppTransitionFutureCallback = callback;
         }
     }
 
@@ -1486,8 +1484,10 @@ public class AppTransition implements Dump {
                     }
                     synchronized (mServiceLock) {
                         mNextAppTransitionAnimationsSpecsPending = false;
-                        overridePendingAppTransitionMultiThumb(specs, mNextAppTransitionCallback,
-                                null /* finishedCallback */, mNextAppTransitionScaleUp);
+                        overridePendingAppTransitionMultiThumb(specs,
+                                mNextAppTransitionFutureCallback, null /* finishedCallback */,
+                                mNextAppTransitionScaleUp);
+                        mNextAppTransitionFutureCallback = null;
                         mWindowSurfacePlacer.requestTraversal();
                     }
                 }