Fix Leg test failures.

frog/leg/ssa/nodes.dart

 // Copyright (c) 2011, 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.
 
 interface HVisitor<R> {
   R visitAdd(HAdd node);
   R visitBitAnd(HBitAnd node);
   R visitBitNot(HBitNot node);
   R visitBitOr(HBitOr node);
   R visitBitXor(HBitXor node);
@@ skipping 1521 matching lines @@
   bool get hasRightQuote() => (flags & HAS_RIGHT_QUOTE) != 0;
   bool get isMultiLine() => (flags & MULTI_LINE) != 0;
   bool get isRaw() => (flags & RAW) != 0;
   String get quoteChar() => ((flags & SINGLE_QUOTED) != 0) ? "'" : '"';
 
   int get contentStart() =>
      hasLeftQuote ? (isRaw ? 1 : 0) + (isMultiLine ? 3 : 1) : 0;
   int get contentEnd() =>
      wrappedString.length - (hasRightQuote ? (isMultiLine ? 3 : 1) : 0);
 
+  /**
+    * Does a conservative test for equality between two quoted strings.
+    * Returns true if the two definitly have the same string.
+    * Returns false if the strings are different, or if it's not possible
+    * to (quickly) determine whether they are equal.
+    */
+  bool definitlyEquals(QuotedString other) {
+    return flags == other.flags && wrappedString == other.wrappedString;
+  }
+
   void printOn(StringBuffer buffer) {
     int start = contentStart;
     int end = contentEnd;
     int length = wrappedString.length;
     if (start == 1 && end == length - 1) {
       wrappedString.printOn(buffer);
     } else {
       String quote = quoteChar;
       buffer.add(quote);
       buffer.add(wrappedString.stringValue.substring(start, end));
@@ skipping 404 matching lines @@
                    HInstruction first,
                    HInstruction second)
       : super(<HInstruction>[first, second]);
   toString() => operation;
   accept(HVisitor visitor) => visitor.visitLogicalOperator(this);
   HInstruction get left() => inputs[0];
   HInstruction get right() => inputs[1];
   HType computeType() => HType.BOOLEAN;
   bool hasExpectedType() => true;
 }