Correctly handle parenthesized percent expressions

Bug: 27496478

A right parenthesis can legitimately follow a +n% expressions without
changing its meaning.

Change-Id: Id6507ee54c82ba22379f28f0a8c32466ef4a7ca7
diff --git a/src/com/android/calculator2/CalculatorExpr.java b/src/com/android/calculator2/CalculatorExpr.java
index 59c800e..f8011e5 100644
--- a/src/com/android/calculator2/CalculatorExpr.java
+++ b/src/com/android/calculator2/CalculatorExpr.java
@@ -1055,7 +1055,7 @@
             return false;
         }
         Operator op = (Operator) mExpr.get(pos + 2);
-        return op.id == R.id.op_add || op.id == R.id.op_sub;
+        return op.id == R.id.op_add || op.id == R.id.op_sub || op.id == R.id.rparen;
     }
 
     /**