Remove DartString from constants.

pkg/compiler/lib/src/constants/expressions.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.
 
 library dart2js.constants.expressions;
 
 import '../common.dart';
 import '../constants/constant_system.dart';
 import '../common_elements.dart';
 import '../elements/entities.dart';
 import '../elements/operators.dart';
 import '../elements/types.dart';
-import '../tree/dartstring.dart' show DartString;
 import '../universe/call_structure.dart' show CallStructure;
 import 'constructors.dart';
 import 'evaluation.dart';
 import 'values.dart';
 
 enum ConstantExpressionKind {
   BINARY,
   BOOL,
   BOOL_FROM_ENVIRONMENT,
   CONCATENATE,
@@ skipping 297 matching lines @@
   }
 
   @override
   void _createStructuredText(StringBuffer sb) {
     sb.write('String(value=${primitiveValue})');
   }
 
   @override
   ConstantValue evaluate(
       EvaluationEnvironment environment, ConstantSystem constantSystem) {
-    return constantSystem.createString(new DartString.literal(primitiveValue));
+    return constantSystem.createString(primitiveValue);
   }
 
   @override
   int _computeHashCode() => 23 * primitiveValue.hashCode;
 
   @override
   bool _equals(StringConstantExpression other) {
     return primitiveValue == other.primitiveValue;
   }
 
@@ skipping 304 matching lines @@
   }
 
   ConstantExpression apply(NormalizedArguments arguments) {
     return new ConcatenateConstantExpression(
         expressions.map((a) => a.apply(arguments)).toList());
   }
 
   @override
   ConstantValue evaluate(
       EvaluationEnvironment environment, ConstantSystem constantSystem) {
-    DartString accumulator;
+    StringBuffer sb = new StringBuffer();
     for (ConstantExpression expression in expressions) {
       ConstantValue value = expression.evaluate(environment, constantSystem);
-      DartString valueString;
-      if (value.isNum || value.isBool || value.isNull) {
+      if (value.isPrimitive) {
         PrimitiveConstantValue primitive = value;
-        valueString =
-            new DartString.literal(primitive.primitiveValue.toString());
-      } else if (value.isString) {
-        PrimitiveConstantValue primitive = value;
-        valueString = primitive.primitiveValue;
+        sb.write(primitive.primitiveValue);
       } else {
         // TODO(johnniwinther): Specialize message to indicated that the problem
         // is not constness but the types of the const expressions.
         return new NonConstantValue();
       }
-      if (accumulator == null) {
-        accumulator = valueString;
-      } else {
-        accumulator = new DartString.concat(accumulator, valueString);
-      }
     }
-    return constantSystem.createString(accumulator);
+    return constantSystem.createString(sb.toString());
   }
 
   @override
   int _computeHashCode() {
     int hashCode = 17 * expressions.length;
     for (ConstantExpression value in expressions) {
       hashCode ^= 19 * value.hashCode;
     }
     return hashCode;
   }
@@ skipping 737 matching lines @@
     ConstantValue defaultConstantValue;
     if (defaultValue != null) {
       defaultConstantValue = defaultValue.evaluate(environment, constantSystem);
     } else {
       defaultConstantValue = constantSystem.createBool(false);
     }
     if (!nameConstantValue.isString) {
       return new NonConstantValue();
     }
     StringConstantValue nameStringConstantValue = nameConstantValue;
-    String text = environment.readFromEnvironment(
-        nameStringConstantValue.primitiveValue.slowToString());
+    String text =
+        environment.readFromEnvironment(nameStringConstantValue.primitiveValue);
     if (text == 'true') {
       return constantSystem.createBool(true);
     } else if (text == 'false') {
       return constantSystem.createBool(false);
     } else {
       return defaultConstantValue;
     }
   }
 
   ConstantExpression apply(NormalizedArguments arguments) {
@@ skipping 42 matching lines @@
     ConstantValue defaultConstantValue;
     if (defaultValue != null) {
       defaultConstantValue = defaultValue.evaluate(environment, constantSystem);
     } else {
       defaultConstantValue = constantSystem.createNull();
     }
     if (!nameConstantValue.isString) {
       return new NonConstantValue();
     }
     StringConstantValue nameStringConstantValue = nameConstantValue;
-    String text = environment.readFromEnvironment(
-        nameStringConstantValue.primitiveValue.slowToString());
+    String text =
+        environment.readFromEnvironment(nameStringConstantValue.primitiveValue);
     int value;
     if (text != null) {
       value = int.parse(text, onError: (_) => null);
     }
     if (value == null) {
       return defaultConstantValue;
     } else {
       return constantSystem.createInt(value);
     }
   }
@@ skipping 44 matching lines @@
     ConstantValue defaultConstantValue;
     if (defaultValue != null) {
       defaultConstantValue = defaultValue.evaluate(environment, constantSystem);
     } else {
       defaultConstantValue = constantSystem.createNull();
     }
     if (!nameConstantValue.isString) {
       return new NonConstantValue();
     }
     StringConstantValue nameStringConstantValue = nameConstantValue;
-    String text = environment.readFromEnvironment(
-        nameStringConstantValue.primitiveValue.slowToString());
+    String text =
+        environment.readFromEnvironment(nameStringConstantValue.primitiveValue);
     if (text == null) {
       return defaultConstantValue;
     } else {
-      return constantSystem.createString(new DartString.literal(text));
+      return constantSystem.createString(text);
     }
   }
 
   ConstantExpression apply(NormalizedArguments arguments) {
     return new StringFromEnvironmentConstantExpression(name.apply(arguments),
         defaultValue != null ? defaultValue.apply(arguments) : null);
   }
 
   @override
   InterfaceType getKnownType(CommonElements commonElements) =>
@@ skipping 354 matching lines @@
     visit(exp.name);
     if (exp.defaultValue != null) {
       sb.write(', defaultValue: ');
       visit(exp.defaultValue);
     }
     sb.write(')');
   }
 
   String toString() => sb.toString();
 }