Make lines and columns one-based in SourceLocation.

pkg/compiler/lib/src/io/position_information.dart

 // Copyright (c) 2015, 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.
 
 /// Source information system mapping that attempts a semantic mapping between
 /// offsets of JavaScript code points to offsets of Dart code points.
 
 library dart2js.source_information.position;
 
 import '../common.dart';
@@ skipping 51 matching lines @@
         closingPosition == other.closingPosition;
   }
 
   /// Create a textual representation of the source information using [uriText]
   /// as the Uri representation.
   String _computeText(String uriText) {
     StringBuffer sb = new StringBuffer();
     sb.write('$uriText:');
     // Use 1-based line/column info to match usual dart tool output.
     if (startPosition != null) {
-      sb.write('[${startPosition.line + 1},'
-          '${startPosition.column + 1}]');
+      sb.write('[${startPosition.line},'
+          '${startPosition.column}]');
     }
     if (closingPosition != null) {
-      sb.write('-[${closingPosition.line + 1},'
-          '${closingPosition.column + 1}]');
+      sb.write('-[${closingPosition.line},'
+          '${closingPosition.column}]');
     }
     return sb.toString();
   }
 
   String get shortText {
     if (startPosition != null) {
       return _computeText(startPosition.sourceUri.pathSegments.last);
     } else {
       return _computeText(closingPosition.sourceUri.pathSegments.last);
     }
@@ skipping 1248 matching lines @@
 
   @override
   CodePosition operator [](js.Node node) {
     CodePosition codePosition = codePositions[node];
     if (codePosition == null) {
       coverage.registerNodesWithoutOffset(node);
     }
     return codePosition;
   }
 }