Introduce CodeBuffer as StringBuffer replacement in compiler.

lib/compiler/implementation/universe.dart

 // Copyright (c) 2012, 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.
 
 class Universe {
-  Map<Element, CodeBlock> generatedCode;
-  Map<Element, CodeBlock> generatedBailoutCode;
+  Map<Element, CodeBuffer> generatedCode;
+  Map<Element, CodeBuffer> generatedBailoutCode;
   final Set<ClassElement> instantiatedClasses;
   final Set<SourceString> instantiatedClassInstanceFields;
   final Set<FunctionElement> staticFunctionsNeedingGetter;
   final Map<SourceString, Set<Selector>> invokedNames;
   final Map<SourceString, Set<Selector>> invokedGetters;
   final Map<SourceString, Set<Selector>> invokedSetters;
   final Map<SourceString, Set<Selector>> fieldGetters;
   final Map<SourceString, Set<Selector>> fieldSetters;
   // TODO(ngeoffray): This should be a Set<Type>.
   final Set<Element> isChecks;
   final RuntimeTypeInformation rti;
 
-  Universe() : generatedCode = new Map<Element, CodeBlock>(),
-               generatedBailoutCode = new Map<Element, CodeBlock>(),
+  Universe() : generatedCode = new Map<Element, CodeBuffer>(),
+               generatedBailoutCode = new Map<Element, CodeBuffer>(),
                instantiatedClasses = new Set<ClassElement>(),
                instantiatedClassInstanceFields = new Set<SourceString>(),
                staticFunctionsNeedingGetter = new Set<FunctionElement>(),
                invokedNames = new Map<SourceString, Set<Selector>>(),
                invokedGetters = new Map<SourceString, Set<Selector>>(),
                invokedSetters = new Map<SourceString, Set<Selector>>(),
                fieldGetters = new Map<SourceString, Set<Selector>>(),
                fieldSetters = new Map<SourceString, Set<Selector>>(),
                isChecks = new Set<Element>(),
                rti = new RuntimeTypeInformation();
 
-  void addGeneratedCode(WorkItem work, CodeBlock codeBlock) {
-    generatedCode[work.element] = codeBlock;
+  void addGeneratedCode(WorkItem work, CodeBuffer codeBuffer) {
+    generatedCode[work.element] = codeBuffer;
   }
 
-  void addBailoutCode(WorkItem work, CodeBlock codeBlock) {
-    generatedBailoutCode[work.element] = codeBlock;
+  void addBailoutCode(WorkItem work, CodeBuffer codeBuffer) {
+    generatedBailoutCode[work.element] = codeBuffer;
   }
 
   bool hasMatchingSelector(Set<Selector> selectors,
                            Element member,
                            Compiler compiler) {
     if (selectors === null) return false;
     for (Selector selector in selectors) {
       if (selector.applies(member, compiler)) return true;
     }
     return false;
@@ skipping 296 matching lines @@
 
     return false;
   }
 
   bool operator ==(other) {
     if (other is !TypedSelector) return false;
     if (other.receiverType !== receiverType) return false;
     return super == other;
   }
 }
-
-class CodeBlock {
-  String code;
-  List<SourceMappingEntry> sourceMappings;
-  CodeBlock(this.code, this.sourceMappings);
-}