Restore previous currentPage in applyLoadPlan in case task is re-ordered

Fix: 186537288
Test: Repeatededly launch task from home and swipe to home, animation is correct
Test: Quick switch, launch task then swipe up, there is no jump
Change-Id: I9fd7416d9811ce4e54a1c6d20374d89d00417cd5
diff --git a/quickstep/src/com/android/quickstep/views/RecentsView.java b/quickstep/src/com/android/quickstep/views/RecentsView.java
index 710a9ab..65ccb13 100644
--- a/quickstep/src/com/android/quickstep/views/RecentsView.java
+++ b/quickstep/src/com/android/quickstep/views/RecentsView.java
@@ -1087,6 +1087,12 @@
             return;
         }
 
+        int currentTaskId = -1;
+        TaskView currentTaskView = getTaskViewAtByAbsoluteIndex(mCurrentPage);
+        if (currentTaskView != null) {
+            currentTaskId = currentTaskView.getTask().key.id;
+        }
+
         // Unload existing visible task data
         unloadVisibleTaskData(TaskView.FLAG_UPDATE_ALL);
 
@@ -1126,6 +1132,11 @@
             } else if (getTaskViewCount() > 0) {
                 setCurrentPage(indexOfChild(getTaskViewAt(0)));
             }
+        } else if (currentTaskId != -1) {
+            currentTaskView = getTaskView(currentTaskId);
+            if (currentTaskView != null) {
+                setCurrentPage(indexOfChild(currentTaskView));
+            }
         }
 
         if (mIgnoreResetTaskId != -1 && getTaskView(mIgnoreResetTaskId) != ignoreResetTaskView) {