Initial 'Extract Method' refactoring implementation.

pkg/analysis_testing/lib/abstract_single_unit.dart

Index: pkg/analysis_testing/lib/abstract_single_unit.dart
diff --git a/pkg/analysis_testing/lib/abstract_single_unit.dart b/pkg/analysis_testing/lib/abstract_single_unit.dart
index 7930d09172bc8f57502712c7292e00510638c280..15e70d6a1fe17542228fd8ea202e7eb8916a5170 100644
--- a/pkg/analysis_testing/lib/abstract_single_unit.dart
+++ b/pkg/analysis_testing/lib/abstract_single_unit.dart
@@ -61,6 +61,10 @@ class AbstractSingleUnitTest extends AbstractContextTest {
     return ElementLocator.locate(node);
   }
 
+  int findEnd(String search) {
+    return findOffset(search) + search.length;
+  }
+
   int findOffset(String search) {
     int offset = testCode.indexOf(search);
     expect(offset, isNonNegative, reason: "Not found '$search' in\n$testCode");