Adds support for remaining generic method syntax constructs.

pkg/compiler/lib/src/dart_backend/backend_ast_to_frontend_ast.dart

Index: pkg/compiler/lib/src/dart_backend/backend_ast_to_frontend_ast.dart
diff --git a/pkg/compiler/lib/src/dart_backend/backend_ast_to_frontend_ast.dart b/pkg/compiler/lib/src/dart_backend/backend_ast_to_frontend_ast.dart
index 1ab7882a44e972e3789ff17ba6003de97e324534..81eae70c8192c51db1bac54801b317ce8eb2c33e 100644
--- a/pkg/compiler/lib/src/dart_backend/backend_ast_to_frontend_ast.dart
+++ b/pkg/compiler/lib/src/dart_backend/backend_ast_to_frontend_ast.dart
@@ -1106,7 +1106,7 @@ class TreePrinter {
           bound =
               makeType(TypeGenerator.createType(typeVariable.element.bound));
         }
-        tree.TypeVariable node = new tree.TypeVariable(id, bound);
+        tree.TypeVariable node = new tree.TypeVariable(id, extendsToken, bound);
         treeElements.setType(node, typeVariable);
         typeVariableList.add(node);
       }