Make lines and columns one-based in SourceLocation.

pkg/compiler/lib/src/io/source_map_builder.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.
 
 library dart2js.source_map_builder;
 
 import 'package:kernel/ast.dart' show Location;
 import '../../compiler_new.dart' show OutputSink, OutputType;
 import '../util/uri_extras.dart' show relativize;
 import '../util/util.dart';
@@ skipping 45 matching lines @@
       int column = kernelLocation.column - 1;
       lineColumnMap.add(line, column, sourceMapEntry);
 
       SourceLocation location = sourceMapEntry.sourceLocation;
       if (location != null) {
         if (location.sourceUri != null) {
           LineColumnMap<SourceMapEntry> sourceLineColumnMap =
               sourceLocationMap.putIfAbsent(location.sourceUri,
                   () => new LineColumnMap<SourceMapEntry>());
           sourceLineColumnMap.add(
-              location.line, location.column, sourceMapEntry);
+              location.line - 1, location.column - 1, sourceMapEntry);
         }
       }
     });
 
     return _build(lineColumnMap);
   }
 
   String _build(LineColumnMap<SourceMapEntry> lineColumnMap) {
     IndexMap<Uri> uriMap = new IndexMap<Uri>();
     IndexMap<String> nameMap = new IndexMap<String>();
@@ skipping 73 matching lines @@
 
       targetColumnEncoder.encode(output, targetColumn);
 
       if (sourceLocation == null) {
         return;
       }
 
       Uri sourceUri = sourceLocation.sourceUri;
       if (sourceUri != null) {
         sourceUriIndexEncoder.encode(output, uriMap[sourceUri]);
-        sourceLineEncoder.encode(output, sourceLocation.line);
-        sourceColumnEncoder.encode(output, sourceLocation.column);
+        sourceLineEncoder.encode(output, sourceLocation.line - 1);
+        sourceColumnEncoder.encode(output, sourceLocation.column - 1);
       }
 
       String sourceName = sourceLocation.sourceName;
       if (sourceName != null) {
         sourceNameIndexEncoder.encode(output, nameMap[sourceName]);
       }
 
       previousSourceLocation = sourceLocation;
     });
   }
@@ skipping 184 matching lines @@
   int register(T element) {
     return map.putIfAbsent(element, () => map.length);
   }
 
   /// Returns the index of [element].
   int operator [](T element) => map[element];
 
   /// Returns the indexed elements.
   Iterable<T> get elements => map.keys;
 }