Merge "Add example to PermissionEnforcer javadoc"

 * PermissionEnforcer to validate the permissions. The methods available are

 * purposely similar to the AIDL annotation syntax.

 *

 * <p>The constructor of the Stub generated by AIDL expects a

 * PermissionEnforcer. It can be based on the current Context. For example:

 *

 * <pre>{@code

 * class MyFoo extends Foo.Stub {

 *     MyFoo(Context context) {

 *         super(PermissionEnforcer.fromContext(context));

 *     }

 *

 *     @Override

 *     @EnforcePermission(android.Manifest.permission.INTERNET)

 *     public MyMethod() {

 *         MyMethod_enforcePermission();

 *     }

 * }

 * }</pre>

 *

 * <p>A {@link android.os.test.FakePermissionEnforcer} is available for unit

 * testing. It can be attached to a mocked Context using:

 * <pre>{@code

 * @Mock private Context mContext;

 *

 * @Before

 * public setUp() {

 *   fakeEnforcer = new FakePermissionEnforcer();

 *   fakeEnforcer.grant(android.Manifest.permission.INTERNET);

 *

 *   doReturn(fakeEnforcer).when(mContext).getSystemService(

                eq(Context.PERMISSION_ENFORCER_SERVICE));

 * }

 * }</pre>

 *

 * @see android.permission.PermissionManager

 *

 * @hide