GN: Use all targets to determine whether a file is generated (for `check`).

tools/gn/header_checker.cc

 // Copyright 2014 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/header_checker.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/files/file_util.h"
@@ skipping 145 matching lines @@
 
   scoped_refptr<base::SequencedWorkerPool> pool(
       new base::SequencedWorkerPool(16, "HeaderChecker"));
   for (const auto& file : files) {
     // Only check C-like source files (RC files also have includes).
     SourceFileType type = GetSourceFileType(file.first);
     if (type != SOURCE_CPP && type != SOURCE_H && type != SOURCE_C &&
         type != SOURCE_M && type != SOURCE_MM && type != SOURCE_RC)
       continue;
 
-    // If any target marks it as generated, don't check it.
+    // If any target marks it as generated, don't check it. We have to check
+    // file_map_, which includes all known files; files only includes those
+    // being checked.
     bool is_generated = false;
-    for (const auto& vect_i : file.second)
+    for (const auto& vect_i : file_map_[file.first])
       is_generated |= vect_i.is_generated;
     if (is_generated)
       continue;
 
     for (const auto& vect_i : file.second) {
       if (vect_i.target->check_includes()) {
         pool->PostWorkerTaskWithShutdownBehavior(
             FROM_HERE,
             base::Bind(&HeaderChecker::DoWork, this, vect_i.target, file.first),
             base::SequencedWorkerPool::BLOCK_SHUTDOWN);
@@ skipping 396 matching lines @@
   if (targets_with_other_toolchains.size() +
       targets_with_matching_toolchains.size() > 1)
     msg += "at least one of ";
   msg += "which should somehow be reachable.";
 
   // Danger: must call CreatePersistentRange to put in Err.
   return Err(CreatePersistentRange(source_file, range),
              "Include not allowed.", msg);
 }