`LineInfo` line-end detection fixes.

pkg/analyzer/test/src/task/options_test.dart

Index: pkg/analyzer/test/src/task/options_test.dart
diff --git a/pkg/analyzer/test/src/task/options_test.dart b/pkg/analyzer/test/src/task/options_test.dart
index 5dddc259ffec9b9a79d6b6c19aaf2840cef9b67d..bf58d00cef58a0a5bed0550209dbe47b58d7aeae 100644
--- a/pkg/analyzer/test/src/task/options_test.dart
+++ b/pkg/analyzer/test/src/task/options_test.dart
@@ -32,6 +32,9 @@ class GenerateOptionsErrorsTaskTest extends AbstractContextTest {
   final optionsFilePath = '/${AnalysisEngine.ANALYSIS_OPTIONS_FILE}';
 
   Source source;
+  LineInfo lineInfo(String source) =>
+      GenerateOptionsErrorsTask.computeLineInfo(source);
+
   @override
   setUp() {
     super.setUp();
@@ -46,6 +49,18 @@ class GenerateOptionsErrorsTaskTest extends AbstractContextTest {
         unorderedEquals([GenerateOptionsErrorsTask.CONTENT_INPUT_NAME]));
   }
 
+  test_compute_lineInfo() {
+    expect(lineInfo('foo\nbar').getLocation(4).lineNumber, 2);
+    expect(lineInfo('foo\nbar').getLocation(4).columnNumber, 1);
+    expect(lineInfo('foo\r\nbar').getLocation(5).lineNumber, 2);
+    expect(lineInfo('foo\r\nbar').getLocation(5).columnNumber, 1);
+    expect(lineInfo('foo\rbar').getLocation(4).lineNumber, 2);
+    expect(lineInfo('foo\rbar').getLocation(4).columnNumber, 1);
+    expect(lineInfo('foo').getLocation(0).lineNumber, 1);
+    expect(lineInfo('foo').getLocation(0).columnNumber, 1);
+    expect(lineInfo('').getLocation(1).lineNumber, 1);
+  }
+
   test_constructor() {
     GenerateOptionsErrorsTask task =
         new GenerateOptionsErrorsTask(context, source);