Add StringSink and update StringBuffer.

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 c3465e8783cec69dd3ac6deea2eea9a8d98de952..807184c7c38d63c0695c27d4d9887cf066bb63b1 100644
--- a/sdk/lib/_internal/compiler/implementation/code_buffer.dart
+++ b/sdk/lib/_internal/compiler/implementation/code_buffer.dart
@@ -20,11 +20,15 @@ class CodeBuffer implements StringBuffer {
     return buffer.isEmpty;
   }
 
+  CodeBuffer add(var object) {
+    write(object);
+    return this;
+  }
   /**
    * Converts [object] to a string and adds it to the buffer. If [object] is a
    * [CodeBuffer], adds its markers to [markers].
    */
-  CodeBuffer add(var object) {
+  CodeBuffer write(var object) {
     if (object is CodeBuffer) {
       return addBuffer(object);
     }
@@ -33,6 +37,10 @@ class CodeBuffer implements StringBuffer {
     return this;
   }
 
+  CodeBuffer writeln(var object) {
+    return write(object).write("\n");
+  }
+
   CodeBuffer addBuffer(CodeBuffer other) {
     if (other.markers.length > 0) {
       CodeBufferMarker firstMarker = other.markers[0];
@@ -46,17 +54,20 @@ class CodeBuffer implements StringBuffer {
       lastBufferOffset = buffer.length + other.lastBufferOffset;
     }
     buffer.add(other.getText());
+    return this;
   }
 
   CodeBuffer addAll(Iterable<Object> iterable) {
     for (Object obj in iterable) {
-      add(obj);
+      write(obj);
     }
     return this;
   }
 
-  CodeBuffer addCharCode(int charCode) {
-    return add(new String.fromCharCodes([charCode]));
+  CodeBuffer addCharCode(int charCode) => writeCharCode(charCode);
+
+  CodeBuffer writeCharCode(int charCode) {
+    return write(new String.fromCharCodes([charCode]));
   }
 
   CodeBuffer clear() {