Fix a dartc error for pkg/http/multipart_test.

pkg/http/test/utils.dart

Index: pkg/http/test/utils.dart
diff --git a/pkg/http/test/utils.dart b/pkg/http/test/utils.dart
index 606bb77cae4e4f0a3e03ccf927c0dca82b9c9b09..4ffa195fd46b0511ae06bf93403800006b28ede1 100644
--- a/pkg/http/test/utils.dart
+++ b/pkg/http/test/utils.dart
@@ -109,6 +109,33 @@ void stopServer() {
   _server = null;
 }
 
+/// Removes eight spaces of leading indentation from a multiline string.
+///
+/// Note that this is very sensitive to how the literals are styled. They should
+/// be:
+///     '''
+///     Text starts on own line. Lines up with subsequent lines.
+///     Lines are indented exactly 8 characters from the left margin.
+///     Close is on the same line.'''
+///
+/// This does nothing if text is only a single line.
+// TODO(nweiz): Make this auto-detect the indentation level from the first
+// non-whitespace line.
+String cleanUpLiteral(String text) {
+  var lines = text.split('\n');
+  if (lines.length <= 1) return text;
+
+  for (var j = 0; j < lines.length; j++) {
+    if (lines[j].length > 8) {
+      lines[j] = lines[j].substring(8, lines[j].length);
+    } else {
+      lines[j] = '';
+    }
+  }
+
+  return lines.join('\n');
+}
+
 /// A matcher that matches JSON that parses to a value that matches the inner
 /// matcher.
 Matcher parse(matcher) => new _Parse(matcher);