From 151778998ae6087c17cae4916a2c02eb59558daa Mon Sep 17 00:00:00 2001
From: Vadim Tryshev <vadimt@google.com>
Date: Fri, 18 Dec 2015 08:01:00 -0800
Subject: [PATCH] Fixing crash in D&D due to race conditions during drag end.

*** MERGING TO MASTER ***

Drag-end event processing for a child view can remove the GroupView,
Which will synchronously call dispatchDetachedFromWindow(), which will
null mChildrenInterestedInDrag.
This causes a crash when trying to clear the map.

Fixing by introducing a local variable.

Bug: 25433279
Change-Id: I2ef88f7f97935dbafda54634831fbbff747b8f2e
(cherry picked from commit 2e2f1066ad89110365cdb504bf6568569d94da58)
---
 core/java/android/view/ViewGroup.java | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/core/java/android/view/ViewGroup.java b/core/java/android/view/ViewGroup.java
index cd93dab0c48bc..1c243929fa49d 100644
--- a/core/java/android/view/ViewGroup.java
+++ b/core/java/android/view/ViewGroup.java
@@ -1419,8 +1419,9 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager
 
         case DragEvent.ACTION_DRAG_ENDED: {
             // Release the bookkeeping now that the drag lifecycle has ended
-            if (mChildrenInterestedInDrag != null) {
-                for (View child : mChildrenInterestedInDrag) {
+            final HashSet<View> childrenInterestedInDrag = mChildrenInterestedInDrag;
+            if (childrenInterestedInDrag != null) {
+                for (View child : childrenInterestedInDrag) {
                     // If a child was interested in the ongoing drag, it's told that it's over
                     if (child.dispatchDragEvent(event)) {
                         retval = true;
@@ -1428,12 +1429,11 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager
                     child.mPrivateFlags2 &= ~View.DRAG_MASK;
                     child.refreshDrawableState();
                 }
-
-                mChildrenInterestedInDrag.clear();
-                if (mCurrentDragStartEvent != null) {
-                    mCurrentDragStartEvent.recycle();
-                    mCurrentDragStartEvent = null;
-                }
+                childrenInterestedInDrag.clear();
+            }
+            if (mCurrentDragStartEvent != null) {
+                mCurrentDragStartEvent.recycle();
+                mCurrentDragStartEvent = null;
             }
 
             if (mIsInterestedInDrag) {