🐣 GN: Print the import trail when parse errors occur.

tools/gn/loader.h

 // 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.
 
 #ifndef TOOLS_GN_LOADER_H_
 #define TOOLS_GN_LOADER_H_
 
 #include <map>
 #include <memory>
 #include <set>
@@ skipping 111 matching lines @@
                         const LocationRange& origin,
                         const SourceFile& file);
   void ScheduleLoadBuildConfig(
       Settings* settings,
       const Scope::KeyValueMap& toolchain_overrides);
 
   // Runs the given file on the background thread. These are called by the
   // input file manager.
   void BackgroundLoadFile(const Settings* settings,
                           const SourceFile& file_name,
+                          const LocationRange& origin,
                           const ParseNode* root);
   void BackgroundLoadBuildConfig(
       Settings* settings,
       const Scope::KeyValueMap& toolchain_overrides,
       const ParseNode* root);
 
   // Posted to the main thread when any file other than a build config file
   // file has completed running.
   void DidLoadFile();
 
@@ skipping 30 matching lines @@
 
   const BuildSettings* build_settings_;
   Label default_toolchain_label_;
 
   // Records for the build config file loads.
   typedef std::map<Label, std::unique_ptr<ToolchainRecord>> ToolchainRecordMap;
   ToolchainRecordMap toolchain_records_;
 };
 
 #endif  // TOOLS_GN_LOADER_H_