Allow closures in string literals in initializer expressions.

sdk/lib/_internal/compiler/implementation/scanner/parser.dart

Index: sdk/lib/_internal/compiler/implementation/scanner/parser.dart
diff --git a/sdk/lib/_internal/compiler/implementation/scanner/parser.dart b/sdk/lib/_internal/compiler/implementation/scanner/parser.dart
index e28b11006338d9038f66990195c978483161746a..2b82c5e1157699ffa7513122829b05d9638a72c2 100644
--- a/sdk/lib/_internal/compiler/implementation/scanner/parser.dart
+++ b/sdk/lib/_internal/compiler/implementation/scanner/parser.dart
@@ -1941,6 +1941,8 @@ class Parser {
   }
 
   Token parseLiteralString(Token token) {
+    bool old = mayParseFunctionExpressions;
+    mayParseFunctionExpressions = true;
     token = parseSingleLiteralString(token);
     int count = 1;
     while (identical(token.kind, STRING_TOKEN)) {
@@ -1950,6 +1952,7 @@ class Parser {
     if (count > 1) {
       listener.handleStringJuxtaposition(count);
     }
+    mayParseFunctionExpressions = old;
     return token;
   }