Implement tracking of BUILD.gn files used to define target, toolchain or

tools/gn/item.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 "tools/gn/item.h"
 
 #include "base/logging.h"
 #include "tools/gn/settings.h"
 
-Item::Item(const Settings* settings, const Label& label)
-    : settings_(settings), label_(label), defined_from_(nullptr) {
-}
+Item::Item(const Settings* settings,
+           const Label& label,
+           const InputFileSet& input_files)
+    : settings_(settings),
+      label_(label),
+      defined_from_(nullptr),
+      input_files_(input_files) {}
 
 Item::~Item() {
 }
 
 Config* Item::AsConfig() {
   return nullptr;
 }
 const Config* Item::AsConfig() const {
   return nullptr;
 }
@@ skipping 25 matching lines @@
     return "toolchain";
   if (AsPool())
     return "pool";
   NOTREACHED();
   return "this thing that I have no idea what it is";
 }
 
 bool Item::OnResolved(Err* err) {
   return true;
 }