Add dart:collection_dev library.

runtime/vm/bootstrap.cc

Index: runtime/vm/bootstrap.cc
diff --git a/runtime/vm/bootstrap.cc b/runtime/vm/bootstrap.cc
index d0e864cea63325a8fbd0d53dc56b94f562963545..5720b0a3c20eecf100d03cf0fca5149cbc6c29ab 100644
--- a/runtime/vm/bootstrap.cc
+++ b/runtime/vm/bootstrap.cc
@@ -48,6 +48,13 @@ RawScript* Bootstrap::LoadCollectionScript(bool patch) {
 }
 
 
+RawScript* Bootstrap::LoadCollectionDevScript(bool patch) {
+  const char* url = patch ? "dart:collection-dev-patch" : "dart:collection-dev";
+  const char* source = patch ? collection_dev_source_ : collection_dev_source_;
+  return LoadScript(url, source, patch);
+}
+
+
 RawScript* Bootstrap::LoadMathScript(bool patch) {
   const char* url = patch ? "dart:math-patch" : "dart:math";
   const char* source = patch ? math_patch_ : math_source_;