GN: Separately track labels and origins for lists of stuff

tools/gn/value_extractors.h

Index: tools/gn/value_extractors.h
diff --git a/tools/gn/value_extractors.h b/tools/gn/value_extractors.h
index 12fff00795dac926631bc0b00f1034448dd8db54..ff1611d6b9cab75bb6ecaa791f1a018d520dc1d9 100644
--- a/tools/gn/value_extractors.h
+++ b/tools/gn/value_extractors.h
@@ -8,6 +8,7 @@
 #include <string>
 #include <vector>
 
+#include "tools/gn/target.h"
 #include "tools/gn/value.h"
 
 class BuildSettings;
@@ -51,10 +52,17 @@ bool ExtractListOfRelativeDirs(const BuildSettings* build_settings,
                                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_