GN: Separately track labels and origins for lists of stuff

tools/gn/config_values_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_CONFIG_VALUES_EXTRACTORS_H_
 #define TOOLS_GN_CONFIG_VALUES_EXTRACTORS_H_
 
 #include <ostream>
 #include <string>
 #include <vector>
@@ skipping 22 matching lines @@
         cur_index_(-1) {
   }
 
   bool done() const {
     return cur_index_ >= static_cast<int>(target_->configs().size());
   }
 
   const ConfigValues& cur() const {
     if (cur_index_ == -1)
       return target_->config_values();
-    return target_->configs()[cur_index_]->config_values();
+    return target_->configs()[cur_index_].ptr->config_values();
+  }
+
+  // Returns the origin of who added this config, if any. This will alwsya be
+  // null for the config values of a target itself.
+  const ParseNode* origin() const {
+    if (cur_index_ == -1)
+      return NULL;
+    return target_->configs()[cur_index_].origin;
   }
 
   void Next() {
     cur_index_++;
   }
 
   // Returns the config holding the current config values, or NULL for those
   // config values associated with the target itself.
   const Config* GetCurrentConfig() const {
     if (cur_index_ == -1)
       return NULL;
-    return target_->configs()[cur_index_];
+    return target_->configs()[cur_index_].ptr;
   }
 
  private:
   const Target* target_;
 
   // Represents an index into the target_'s configs() or, when -1, the config
   // values on the target itself.
   int cur_index_;
 };
 
@@ skipping 22 matching lines @@
 }
 
 // Writes the values out as strings with no transformation.
 void RecursiveTargetConfigStringsToStream(
     const Target* target,
     const std::vector<std::string>& (ConfigValues::* getter)() const,
     const EscapeOptions& escape_options,
     std::ostream& out);
 
 #endif  // TOOLS_GN_CONFIG_VALUES_EXTRACTORS_H_