Reland transformation of async functions.

runtime/vm/parser.h

Index: runtime/vm/parser.h
diff --git a/runtime/vm/parser.h b/runtime/vm/parser.h
index bd7c3d2e384e0452c93fa7b7f51ad32c5d553639..b2fbfe64f738404fcdd7f834e1e90183c2e39638 100644
--- a/runtime/vm/parser.h
+++ b/runtime/vm/parser.h
@@ -363,6 +363,8 @@ class Parser : public ValueObject {
   void ParseTopLevelAccessor(TopLevel* top_level, intptr_t metadata_pos);
   RawArray* EvaluateMetadata();
 
+  RawFunction::AsyncModifier ParseFunctionModifier();
+
   // Support for parsing libraries.
   RawObject* CallLibraryTagHandler(Dart_LibraryTag tag,
                                    intptr_t token_pos,
@@ -463,6 +465,7 @@ class Parser : public ValueObject {
                                  Array* default_parameter_values);
   SequenceNode* ParseFunc(const Function& func,
                           Array* default_parameter_values);
+  RawClass* GetClassForAsync(const String& class_name);
 
   void ParseNativeFunctionBlock(const ParamList* params, const Function& func);
 
@@ -483,7 +486,12 @@ class Parser : public ValueObject {
   void OpenBlock();
   void OpenLoopBlock();
   void OpenFunctionBlock(const Function& func);
+  RawFunction* OpenAsyncFunction(intptr_t formal_param_pos);
   SequenceNode* CloseBlock();
+  SequenceNode* CloseAsyncFunction(const Function& closure,
+                                   SequenceNode* closure_node);
+  void CloseAsyncClosure(SequenceNode* body);
+
 
   LocalVariable* LookupPhaseParameter();
   LocalVariable* LookupReceiver(LocalScope* from_scope, bool test_only);