Converting long item IDs to int

> Items ids were already being typecasted to int when being bound on the UI
> Using a consistent type allow better use of platform data-structures
> Adding IntArray and IntSet as a replacement for various Collection classes

Change-Id: Id3c650ed2420c2bfca3bd7671d2b705b56112371

src/com/android/launcher3/util/IntSet.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.launcher3.util;
+
+import java.util.Arrays;
+
+/**
+ * A wrapper over IntArray implementing a growing set of int primitives.
+ */
+public class IntSet {
+
+    final IntArray mArray = new IntArray();
+
+    /**
+     * Appends the specified value to the set if it does not exist.
+     */
+    public void add(int value) {
+        int index = Arrays.binarySearch(mArray.mValues, 0, mArray.mSize, value);
+        if (index < 0) {
+            mArray.add(-index - 1, value);
+        }
+    }
+
+    public boolean contains(int value) {
+        return Arrays.binarySearch(mArray.mValues, 0, mArray.mSize, value) >= 0;
+    }
+
+    public boolean isEmpty() {
+        return mArray.isEmpty();
+    }
+
+    /**
+     * Returns the number of values in this set.
+     */
+    public int size() {
+        return mArray.size();
+    }
+}