Add quotes around strings when generating source from the token stream.

vm/snapshot_test.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "include/dart_debugger_api.h"
 #include "platform/assert.h"
 #include "vm/bigint_operations.h"
 #include "vm/class_finalizer.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_api_message.h"
@@ skipping 702 matching lines @@
   EXPECT(root->value.as_byte_array.values == NULL);
   CheckEncodeDecodeMessage(root);
 }
 
 
 TEST_CASE(SerializeScript) {
   const char* kScriptChars =
       "class A {\n"
       "  static bar() { return 42; }\n"
       "  static fly() { return 5; }\n"
+      "  static s1() { return 'this is a string in the source'; }\n"
+      "  static s2() { return 'this is a \"string\" in the source'; }\n"
+      "  static s3() { return 'this is a \\\'string\\\' in \"the\" source'; }\n"
+      "  static s4() { return 'this \"is\" a \"string\" in \"the\" source'; }\n"
       "}\n";
 
   String& url = String::Handle(String::New("dart-test:SerializeScript"));
   String& source = String::Handle(String::New(kScriptChars));
   Script& script = Script::Handle(Script::New(url, source, RawScript::kSource));
   const String& lib_url = String::Handle(String::NewSymbol("TestLib"));
   Library& lib = Library::Handle(Library::New(lib_url));
   lib.Register();
   EXPECT(CompilerTest::TestCompileScript(lib, script));
 
@@ skipping 805 matching lines @@
   EXPECT(Dart_ErrorHasException(result));
   EXPECT_SUBSTRING("Exception: nulltruefalse1234563.14[]100123456789\n",
                    Dart_GetError(result));
 
   Dart_ExitScope();
 }
 
 #endif  // defined(TARGET_ARCH_IA32) || defined(TARGET_ARCH_X64).
 
 }  // namespace dart