Allow creation and modification of scopes in GN.

tools/gn/loader_unittest.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <map>
 #include <utility>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/run_loop.h"
@@ skipping 78 matching lines @@
 }
 
 bool MockInputFileManager::HasTwoPending(const SourceFile& f1,
                                          const SourceFile& f2) const {
   if (pending_.size() != 2u)
     return false;
   return pending_[0].first == f1 && pending_[1].first == f2;
 }
 
 void MockInputFileManager::IssueAllPending() {
-  BlockNode block;  // Default response.
+  BlockNode block(BlockNode::DISCARDS_RESULT);  // Default response.
 
   for (const auto& cur : pending_) {
     CannedResponseMap::const_iterator found = canned_responses_.find(cur.first);
     if (found == canned_responses_.end())
       cur.second.Run(&block);
     else
       cur.second.Run(found->second->root.get());
   }
   pending_.clear();
 }
@@ skipping 67 matching lines @@
   loader->Load(third_file, LocationRange(), second_tc);
   EXPECT_TRUE(mock_ifm_.HasOnePending(build_config));
 
   // Running the build config file should make our third file pending.
   mock_ifm_.IssueAllPending();
   base::RunLoop().RunUntilIdle();
   EXPECT_TRUE(mock_ifm_.HasTwoPending(second_file, third_file));
 
   EXPECT_FALSE(scheduler_.is_failed());
 }