Make lines and columns one-based in SourceLocation.

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

Index: pkg/compiler/lib/src/io/start_end_information.dart
diff --git a/pkg/compiler/lib/src/io/start_end_information.dart b/pkg/compiler/lib/src/io/start_end_information.dart
index 3840b77b93eb8eba0117ebd46e224d7959281994..8456cd709fac47aec52dd4172e2e13438d839ba1 100644
--- a/pkg/compiler/lib/src/io/start_end_information.dart
+++ b/pkg/compiler/lib/src/io/start_end_information.dart
@@ -91,10 +91,9 @@ class StartEndSourceInformation extends SourceInformation {
   String _computeText(String uriText) {
     StringBuffer sb = new StringBuffer();
     sb.write('$uriText:');
-    // Use 1-based line/startPosition info to match usual dart tool output.
-    sb.write('[${startPosition.line + 1},${startPosition.column + 1}]');
+    sb.write('[${startPosition.line},${startPosition.column}]');
     if (endPosition != null) {
-      sb.write('-[${endPosition.line + 1},${endPosition.column + 1}]');
+      sb.write('-[${endPosition.line},${endPosition.column}]');
     }
     return sb.toString();
   }