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

tools/gn/target.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/target.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 
@@ skipping 257 matching lines @@
   check".
 
   A target's "data_deps" are guaranteed to be built whenever the target is
   built, but the ordering is not defined. The meaning of this is dependencies
   required at runtime. Currently data deps will be complete before the target
   is linked, but this is not semantically guaranteed and this is undesirable
   from a build performance perspective. Since we hope to change this in the
   future, do not rely on this behavior.
 )";
 
-Target::Target(const Settings* settings, const Label& label)
-    : Item(settings, label),
+Target::Target(const Settings* settings,
+               const Label& label,
+               const InputFileSet& input_files)
+    : Item(settings, label, input_files),
       output_type_(UNKNOWN),
       output_prefix_override_(false),
       output_extension_set_(false),
       all_headers_public_(true),
       check_includes_(true),
       complete_static_lib_(false),
       testonly_(false),
-      toolchain_(nullptr) {
-}
+      toolchain_(nullptr) {}
 
 Target::~Target() {
 }
 
 // static
 const char* Target::GetStringForOutputType(OutputType type) {
   switch (type) {
     case UNKNOWN:
       return "unknown";
     case GROUP:
@@ skipping 556 matching lines @@
     check_data_deps = g_scheduler->IsFileGeneratedByWriteRuntimeDeps(out_file);
     // Check object files (much slower and very rare) only if the "normal"
     // output check failed.
     consider_object_files = !check_data_deps;
     if (!EnsureFileIsGeneratedByDependency(this, out_file, true,
                                            consider_object_files,
                                            check_data_deps, &seen_targets))
       g_scheduler->AddUnknownGeneratedInput(this, source);
   }
 }