Keyboard.Key#onReleased() should handle inside parameter.

The boolean parameter of Keyboard.Key#onReleased(boolean) has
been somehow ignored since Capcake.  With this CL, that method
starts working as documented.

Alternatively we could fix the issue when and only when the
application's targetSdkVersion >= 23.  We didn't do that because:
- Although Keyboard.Key class is a public API, it is supposed to
  be used almost only by android.inputmethodservice.KeyboardView.
  The risk of unwanted compatibility problems is low.
- Fixing that is beneficial for users because it actually fixes
  UX issue when applications/IMEs that still rely on KeyboardView
  run in Android M.
- All the fields that are related to Keyboard.Key#onReleased are
  public fields so developers can easily work around anyway.

Bug: 21446448
Change-Id: I392166c77cd9dd2c432dc4f1274312f8355de02b

core/java/android/inputmethodservice/Keyboard.java

@@ -400,16 +400,26 @@ public class Keyboard {
         public void onPressed() {
             pressed = !pressed;
         }
-        
+
         /**
-         * Changes the pressed state of the key. If it is a sticky key, it will also change the
-         * toggled state of the key if the finger was release inside.
-         * @param inside whether the finger was released inside the key
+         * Changes the pressed state of the key.
+         *
+         * <p>Toggled state of the key will be flipped when all the following conditions are
+         * fulfilled:</p>
+         *
+         * <ul>
+         *     <li>This is a sticky key, that is, {@link #sticky} is {@code true}.
+         *     <li>The parameter {@code inside} is {@code true}.
+         *     <li>{@link Build.VERSION.SDK_INT} is greater than {@link VERSION_CODES.LOLLIPOP_MR1}.
+         * </ul>
+         *
+         * @param inside whether the finger was released inside the key. Works only on Android M and
+         * later. See the method document for details.
          * @see #onPressed()
          */
         public void onReleased(boolean inside) {
             pressed = !pressed;
-            if (sticky) {
+            if (sticky && inside) {
                 on = !on;
             }
         }