Add indexOf method to ArrayMap & ArraySet

Getting the indexOf is useful for doing compound operations
like:

int i = set.indexOf(key);
if (i >= 0) {
    Object o = set.valueAt(i);
    o.blah();
    set.removeAt(i);
}

Change-Id: I3d4b77d1461ba969fc6b4d332d52d4d084b5b53c

api/current.txt

@@ -31988,6 +31988,7 @@ package android.util {
     method public void ensureCapacity(int);
     method public java.util.Set<java.util.Map.Entry<K, V>> entrySet();
     method public V get(java.lang.Object);
+    method public int indexOfKey(java.lang.Object);
     method public boolean isEmpty();
     method public K keyAt(int);
     method public java.util.Set<K> keySet();

core/java/android/util/ArrayMap.java

@@ -323,7 +323,17 @@ public final class ArrayMap<K, V> implements Map<K, V> {
      */
     @Override
     public boolean containsKey(Object key) {
-        return key == null ? (indexOfNull() >= 0) : (indexOf(key, key.hashCode()) >= 0);
+        return indexOfKey(key) >= 0;
+    }
+
+    /**
+     * Returns the index of a key in the set.
+     *
+     * @param key The key to search for.
+     * @return Returns the index of the key if it exists, else a negative integer.
+     */
+    public int indexOfKey(Object key) {
+        return key == null ? indexOfNull() : indexOf(key, key.hashCode());
     }
 
     int indexOfValue(Object value) {
@@ -365,7 +375,7 @@ public final class ArrayMap<K, V> implements Map<K, V> {
      */
     @Override
     public V get(Object key) {
-        final int index = key == null ? indexOfNull() : indexOf(key, key.hashCode());
+        final int index = indexOfKey(key);
         return index >= 0 ? (V)mArray[(index<<1)+1] : null;
     }
 
@@ -561,7 +571,7 @@ public final class ArrayMap<K, V> implements Map<K, V> {
      */
     @Override
     public V remove(Object key) {
-        int index = key == null ? indexOfNull() : indexOf(key, key.hashCode());
+        final int index = indexOfKey(key);
         if (index >= 0) {
             return removeAt(index);
         }
@@ -747,7 +757,7 @@ public final class ArrayMap<K, V> implements Map<K, V> {
 
                 @Override
                 protected int colIndexOfKey(Object key) {
-                    return key == null ? indexOfNull() : indexOf(key, key.hashCode());
+                    return indexOfKey(key);
                 }
 
                 @Override

core/java/android/util/ArraySet.java

@@ -291,7 +291,17 @@ public final class ArraySet<E> implements Collection<E>, Set<E> {
      */
     @Override
     public boolean contains(Object key) {
-        return key == null ? (indexOfNull() >= 0) : (indexOf(key, key.hashCode()) >= 0);
+        return indexOf(key) >= 0;
+    }
+
+    /**
+     * Returns the index of a value in the set.
+     *
+     * @param key The value to search for.
+     * @return Returns the index of the value if it exists, else a negative integer.
+     */
+    public int indexOf(Object key) {
+        return key == null ? indexOfNull() : indexOf(key, key.hashCode());
     }
 
     /**
@@ -396,7 +406,7 @@ public final class ArraySet<E> implements Collection<E>, Set<E> {
      */
     @Override
     public boolean remove(Object object) {
-        int index = object == null ? indexOfNull() : indexOf(object, object.hashCode());
+        final int index = indexOf(object);
         if (index >= 0) {
             removeAt(index);
             return true;
@@ -586,12 +596,12 @@ public final class ArraySet<E> implements Collection<E>, Set<E> {
 
                 @Override
                 protected int colIndexOfKey(Object key) {
-                    return key == null ? indexOfNull() : indexOf(key, key.hashCode());
+                    return indexOf(key);
                 }
 
                 @Override
                 protected int colIndexOfValue(Object value) {
-                    return value == null ? indexOfNull() : indexOf(value, value.hashCode());
+                    return indexOf(value);
                 }
 
                 @Override