Formatter: don't indent EOL comment at the beginning of a line.

pkg/analyzer/lib/src/services/formatter_impl.dart

 // Copyright (c) 2013, 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.
 
 library formatter_impl;
 
 import 'dart:math';
 
 import 'package:analyzer/analyzer.dart';
 import 'package:analyzer/src/generated/parser.dart';
@@ skipping 1668 matching lines @@
     writer.newlines(lines);
   }
 
   ensureTrailingNewline() {
     if (writer.lastToken is! NewlineToken) {
       writer.newline();
     }
   }
 
 
+  /// Test if this EOL [comment] is at the beginning of a line.
+  bool isAtBOL(Token comment) =>
+      lineInfo.getLocation(comment.offset).columnNumber == 1;
+
   /// Test if this [comment] is at the end of a line.
   bool isAtEOL(Token comment) =>
       comment != null && comment.toString().trim().startsWith(twoSlashes) &&
       sameLine(comment, previousToken);
 
   /// Emit this [comment], inserting leading whitespace if appropriate.
   emitComment(Token comment, Token previousToken) {
     if (!writer.currentLine.isWhitespace() && previousToken != null) {
       var ws = countSpacesBetween(previousToken, comment);
       // Preserve one space but no more
       if (ws > 0 && leadingSpaces == 0) {
         space();
       }
     }
 
+    // Don't indent commented-out lines
+    if (isAtBOL(comment)) {
+      writer.currentLine.clear();
+    }
+
     append(comment.toString().trim());
   }
 
   /// Count spaces between these tokens.  Tokens on different lines return 0.
   int countSpacesBetween(Token last, Token current) => isEOF(last) ||
       countNewlinesBetween(last, current) > 0 ? 0 : current.offset - last.end;
 
   /// Count the blanks between these two nodes.
   int countBlankLinesBetween(AstNode lastNode, AstNode currentNode) =>
       countNewlinesBetween(lastNode.endToken, currentNode.beginToken);
@@ skipping 54 matching lines @@
     var lastLine =
         lineInfo.getLocation(lastOffset).lineNumber;
     var currentLine =
         lineInfo.getLocation(currentOffset).lineNumber;
     return currentLine - lastLine;
   }
 
   String toString() => writer.toString();
 
 }