VM: Remove _leftShiftWithMask32.

runtime/lib/bigint.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 /*
  * Copyright (c) 2003-2005  Tom Wu
@@ skipping 1318 matching lines @@
         if (bx >= _DIGIT_BITS) {
           bx -= _DIGIT_BITS;
           dx++;
         }
       }
       str._setAt(--cx, _IntegerImplementation._digits.codeUnitAt(ch));
     } while (cx > firstcx);
     return str;
   }
 
-  _leftShiftWithMask32(int count, int mask) {
-    if (_used == 0) return 0;
-    if (count is! _Smi) {
-      _shlFromInt(count);  // Throws out of memory exception.
-    }
-    assert(_DIGIT_BITS == 32);  // Otherwise this code needs to be revised.
-    if (count > 31) return 0;
-    return (_digits[0] << count) & mask;
-  }
-
   int _bitAndFromInteger(int other) {
     return other._toBigint()._and(this)._toValidInt();
   }
   int _bitOrFromInteger(int other) {
     return other._toBigint()._or(this)._toValidInt();
   }
   int _bitXorFromInteger(int other) {
     return other._toBigint()._xor(this)._toValidInt();
   }
   int _addFromInteger(int other) {
@@ skipping 731 matching lines @@
 
   int _mul(Uint32List x_digits, int x_used,
            Uint32List y_digits, int y_used,
            Uint32List r_digits) {
     var r_used = _Bigint._mulDigits(x_digits, x_used,
                                     y_digits, y_used,
                                     r_digits);
     return _reduce(r_digits, r_used);
   }
 }