GN: Separately track labels and origins for lists of stuff

tools/gn/value_extractors.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_VALUE_EXTRACTORS_H_
 #define TOOLS_GN_VALUE_EXTRACTORS_H_
 
 #include <string>
 #include <vector>
 
+#include "tools/gn/target.h"
 #include "tools/gn/value.h"
 
 class BuildSettings;
 class Err;
 class Label;
 class SourceDir;
 class SourceFile;
 
 // Sets the error and returns false on failure.
 template<typename T, class Converter>
@@ skipping 23 matching lines @@
                                 std::vector<SourceFile>* files,
                                 Err* err);
 
 // Looks for a list of source directories relative to a given current dir.
 bool ExtractListOfRelativeDirs(const BuildSettings* build_settings,
                                const Value& value,
                                const SourceDir& current_dir,
                                std::vector<SourceDir>* dest,
                                Err* err);
 
+// Extracts the list of labels and their origins to the given vector. Only the
+// labels are filled in, the ptr for each pair in the vector will be null.
 bool ExtractListOfLabels(const Value& value,
                          const SourceDir& current_dir,
                          const Label& current_toolchain,
-                         std::vector<Label>* dest,
+                         LabelConfigVector* dest,
+                         Err* err);
+bool ExtractListOfLabels(const Value& value,
+                         const SourceDir& current_dir,
+                         const Label& current_toolchain,
+                         LabelTargetVector* dest,
                          Err* err);
 
 #endif  // TOOLS_GN_VALUE_EXTRACTORS_H_