Fix stale QuadItem removal after ClusterItem position updates

clustering/src/main/java/com/google/maps/android/clustering/algo/NonHierarchicalDistanceBasedAlgorithm.kt

@@ -47,6 +47,7 @@ open class NonHierarchicalDistanceBasedAlgorithm<T : ClusterItem> : AbstractAlgo
      */
     @JvmField
     protected val mItems: MutableCollection<QuadItem<T>> = LinkedHashSet()
+    protected val mItemMap = HashMap<T, QuadItem<T>>()
 
     /**
      * Any modifications should be synchronized on mQuadTree.
@@ -61,6 +62,7 @@ open class NonHierarchicalDistanceBasedAlgorithm<T : ClusterItem> : AbstractAlgo
         synchronized(mQuadTree) {
             val result = mItems.add(quadItem)
             if (result) {
+                mItemMap[item] = quadItem
                 mQuadTree.add(quadItem)
             }
             return result
@@ -81,16 +83,17 @@ open class NonHierarchicalDistanceBasedAlgorithm<T : ClusterItem> : AbstractAlgo
     override fun clearItems() {
         synchronized(mQuadTree) {
             mItems.clear()
+            mItemMap.clear()
             mQuadTree.clear()
         }
     }
 
     override fun removeItem(item: T): Boolean {
         // QuadItem delegates hashcode() and equals() to its item so,
         //   removing any QuadItem to that item will remove the item
-        val quadItem = QuadItem(item)
         synchronized(mQuadTree) {
-            val result = mItems.remove(quadItem)
+            val quadItem = mItemMap.remove(item)
+            val result = quadItem != null && mItems.remove(quadItem)
             if (result) {
                 mQuadTree.remove(quadItem)
             }
@@ -104,8 +107,8 @@ open class NonHierarchicalDistanceBasedAlgorithm<T : ClusterItem> : AbstractAlgo
             for (item in items) {
                 // QuadItem delegates hashcode() and equals() to its item so,
                 //   removing any QuadItem to that item will remove the item
-                val quadItem = QuadItem(item)
-                val individualResult = mItems.remove(quadItem)
+                val quadItem = mItemMap.remove(item)
+                val individualResult = quadItem != null && mItems.remove(quadItem)
                 if (individualResult) {
                     mQuadTree.remove(quadItem)
                     result = true

clustering/src/test/java/com/google/maps/android/clustering/QuadItemTest.java

@@ -98,7 +98,7 @@ public void testInsertionOrder() {
   }
 
   private static class TestingItem implements ClusterItem {
-    private final LatLng mPosition;
+    private LatLng mPosition;
     private String mTitle;
 
     TestingItem(String title, double lat, double lng) {
@@ -110,6 +110,9 @@ private static class TestingItem implements ClusterItem {
       mTitle = "";
       mPosition = new LatLng(lat, lng);
     }
+    public void setPosition(double lat, double lng) {
+    mPosition = new LatLng(lat, lng);
+    }
 
     @NonNull
     @Override