Improve the memory consumption and performance of our string buffer implementation.

sdk/lib/_internal/compiler/implementation/code_buffer.dart

Index: sdk/lib/_internal/compiler/implementation/code_buffer.dart
diff --git a/sdk/lib/_internal/compiler/implementation/code_buffer.dart b/sdk/lib/_internal/compiler/implementation/code_buffer.dart
index 4934ea3c7d6a9bbc75a35781b6f10c3ce00029d6..f63a99a519dc1761a8675f83361ca68555b2901d 100644
--- a/sdk/lib/_internal/compiler/implementation/code_buffer.dart
+++ b/sdk/lib/_internal/compiler/implementation/code_buffer.dart
@@ -5,22 +5,18 @@
 part of dart2js;
 
 class CodeBuffer implements StringBuffer {
-  StringBuffer buffer;
-  List<CodeBufferMarker> markers;
+
+  StringBuffer buffer = new StringBuffer();
+  List<CodeBufferMarker> markers = new List<CodeBufferMarker>();
+
   int lastBufferOffset = 0;
   int mappedRangeCounter = 0;
 
-  CodeBuffer()
-      : buffer = new StringBuffer(),
-        markers = new List<CodeBufferMarker>();
+  CodeBuffer();

[Lasse Reichstein Nielsen, 2013/09/20 11:40:17]

You can even remove the constructor entirely.
Probably too confusing.

 
   int get length => buffer.length;
-
-  bool get isEmpty {
-    return buffer.isEmpty;
-  }
-
-  bool get isNotEmpty => !isEmpty;
+  bool get isEmpty => buffer.isEmpty;
+  bool get isNotEmpty => buffer.isNotEmpty;
 
   CodeBuffer add(var object) {
     write(object);
@@ -81,7 +77,8 @@ class CodeBuffer implements StringBuffer {
   CodeBuffer addCharCode(int charCode) => writeCharCode(charCode);
 
   CodeBuffer writeCharCode(int charCode) {
-    return write(new String.fromCharCodes([charCode]));

[Lasse Reichstein Nielsen, 2013/09/20 11:40:17]

Ouch. How much would you gain from just this change?

+    buffer.writeCharCode(charCode);
+    return this;
   }
 
   CodeBuffer clear() {