Fix an off-by-one bug between stack_trace and source_maps.

R=kevmoo@google.com

Review URL: https://codereview.chromium.org//1113453006

CHANGELOG.md

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b13f72f..81f21e8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 1.0.2
+
+* Fix an off-by-one bug that was causing line numbers to be slightly off.
+
 ## 1.0.1
 
 * Don't crash when mapping stack chains.

lib/source_map_stack_trace.dart

diff --git a/lib/source_map_stack_trace.dart b/lib/source_map_stack_trace.dart
index a5a22b3..41072e4 100644
--- a/lib/source_map_stack_trace.dart
+++ b/lib/source_map_stack_trace.dart
@@ -51,7 +51,10 @@
 
     // If there's no column, try using the first column of the line.
     var column = frame.column == null ? 0 : frame.column;
-    var span = sourceMap.spanFor(frame.line, column);
+
+    // Subtract 1 because stack traces use 1-indexed lines and columns and
+    // source maps uses 0-indexed.
+    var span = sourceMap.spanFor(frame.line - 1, column - 1);
 
     // If we can't find a source span, ignore the frame. It's probably something
     // internal that the user doesn't care about.

pubspec.yaml

diff --git a/pubspec.yaml b/pubspec.yaml
index afa10ad..a44df62 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: source_map_stack_trace
-version: 1.0.1
+version: 1.0.2
 description: >
   A package for applying source maps to stack traces.
 author: Dart Team <misc@dartlang.org>