dart2js: Use frequency of occurence to sort metadata indices.

pkg/js_ast/lib/src/printer.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.
 
 part of js_ast;
 
 
 class JavaScriptPrintingOptions {
   final bool shouldCompressOutput;
   final bool minifyLocalVariables;
@@ skipping 934 matching lines @@
   }
 
   @override
   void visitFun(Fun fun) {
     VarCollector vars = new VarCollector();
     vars.visitFun(fun);
     currentNode.closingPosition = functionOut(fun, null, vars);
   }
 
   @override
-  void visitLiteralBool(LiteralBool node) {
+  visitDeferredExpression(DeferredExpression node) {
+    // Continue printing with the expression value.
+    assert(node.precedenceLevel == node.value.precedenceLevel);
+    node.value.accept(this);
+  }
+
+  outputNumberWithRequiredWhitespace(String number) {
+    int charCode = number.codeUnitAt(0);
+    if (charCode == charCodes.$MINUS && lastCharCode == charCodes.$MINUS) {
+      out(" ", isWhitespace: true);
+    }
+    out(number);
+  }
+
+  @override
+  visitDeferredNumber(DeferredNumber node) {
+    outputNumberWithRequiredWhitespace("${node.value}");
+  }
+
+  @override
+  visitDeferredString(DeferredString node) {
+    out(node.value);
+  }
+
+  @override
+  visitLiteralBool(LiteralBool node) {
     out(node.value ? "true" : "false");
   }
 
   @override
   void visitLiteralString(LiteralString node) {
     out(node.value);
   }
 
   @override
-  void visitLiteralNumber(LiteralNumber node) {
-    int charCode = node.value.codeUnitAt(0);
-    if (charCode == charCodes.$MINUS && lastCharCode == charCodes.$MINUS) {
-      out(" ", isWhitespace: true);
-    }
-    out(node.value);
+  visitStringConcatenation(StringConcatenation node) {
+    node.visitChildren(this);
   }
 
   @override
+  visitLiteralNumber(LiteralNumber node) {
+    outputNumberWithRequiredWhitespace(node.value);
+  }
+
+  @override
   void visitLiteralNull(LiteralNull node) {
     out("null");
   }
 
   @override
   void visitArrayInitializer(ArrayInitializer node) {
     out("[");
     List<Expression> elements = node.elements;
     for (int i = 0; i < elements.length; i++) {
       Expression element = elements[i];
@@ skipping 22 matching lines @@
 
   @override
   void visitObjectInitializer(ObjectInitializer node) {
     // Print all the properties on one line until we see a function-valued
     // property.  Ideally, we would use a proper pretty-printer to make the
     // decision based on layout.
     List<Property> properties = node.properties;
     out("{");
     indentMore();
     for (int i = 0; i < properties.length; i++) {
-      Expression value = properties[i].value;
       if (i != 0) {
         out(",");
         if (node.isOneLiner) spaceOut();
       }
       if (!node.isOneLiner) {
         forceLine();
         indent();
       }
       visit(properties[i]);
     }
@@ skipping 398 matching lines @@
     }
   }
 
   EnterExitNode exitNode(JavaScriptPrintingContext context, int position) {
     // Enter must happen before exit.
     addToNode(context, position);
     context.exitNode(node, startPosition, position, closingPosition);
     return parent;
   }
 }