dart2js: Use js('source') instead of js['source'] to invoke JS mini-parser

sdk/lib/_internal/compiler/implementation/js/builder.dart

Index: sdk/lib/_internal/compiler/implementation/js/builder.dart
diff --git a/sdk/lib/_internal/compiler/implementation/js/builder.dart b/sdk/lib/_internal/compiler/implementation/js/builder.dart
index 54924661451afbe5d21a995fef2307daf70a8286..16f2b5d03d92fc39c762a6669508fcc28eedfef5 100644
--- a/sdk/lib/_internal/compiler/implementation/js/builder.dart
+++ b/sdk/lib/_internal/compiler/implementation/js/builder.dart
@@ -10,20 +10,10 @@ part of js;
 class JsBuilder {
   const JsBuilder();
 
-  Expression operator [](String source) {
+  Expression call(String source) {
     return new MiniJsParser(source).expression();
   }
 
-  // TODO(ahe): Remove this method.
-  Binary equals(Expression left, Expression right) {
-    return new Binary('==', left, right);
-  }
-
-  // TODO(ahe): Remove this method.
-  Binary strictEquals(Expression left, Expression right) {
-    return new Binary('===', left, right);
-  }
-
   LiteralString string(String value) => new LiteralString('"$value"');
 
   If if_(condition, thenPart, [elsePart]) {
@@ -92,7 +82,7 @@ class JsBuilder {
     if (expression is Expression) {
       return expression;
     } else if (expression is String) {
-      return this[expression];
+      return this(expression);
     } else if (expression is num) {
       return new LiteralNumber('$expression');
     } else if (expression is bool) {