Check for inputs not generated by deps

tools/gn/filesystem_utils.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/filesystem_utils.h"
 
 #include <algorithm>
 
 #include "base/files/file_util.h"
 #include "base/logging.h"
@@ skipping 292 matching lines @@
   int end = cur;
   cur--;  // Skip before the last slash.
 
   for (; cur >= 0; cur--) {
     if (dir_string[cur] == '/')
       return base::StringPiece(&dir_string[cur + 1], end - cur - 1);
   }
   return base::StringPiece(&dir_string[0], end);
 }
 
-bool EnsureStringIsInOutputDir(const SourceDir& dir,
+bool IsStringInOutputDir(const SourceDir& output_dir, const std::string& str) {
+  // This check will be wrong for all proper prefixes "e.g. "/output" will
+  // match "/out" but we don't really care since this is just a sanity check.
+  const std::string& dir_str = output_dir.value();
+  return str.compare(0, dir_str.length(), dir_str) == 0;
+}
+
+bool EnsureStringIsInOutputDir(const SourceDir& output_dir,
                                const std::string& str,
                                const ParseNode* origin,
                                Err* err) {
-  // This check will be wrong for all proper prefixes "e.g. "/output" will
-  // match "/out" but we don't really care since this is just a sanity check.
-  const std::string& dir_str = dir.value();
-  if (str.compare(0, dir_str.length(), dir_str) == 0)
+  if (IsStringInOutputDir(output_dir, str))
     return true;  // Output directory is hardcoded.
 
   *err = Err(origin, "File is not inside output directory.",
       "The given file should be in the output directory. Normally you would "
       "specify\n\"$target_out_dir/foo\" or "
       "\"$target_gen_dir/foo\". I interpreted this as\n\""
       + str + "\".");
   return false;
 }
 
@@ skipping 478 matching lines @@
 
 SourceDir GetCurrentOutputDir(const Scope* scope) {
   return GetOutputDirForSourceDirAsOutputFile(
       scope->settings(), scope->GetSourceDir()).AsSourceDir(
           scope->settings()->build_settings());
 }
 
 SourceDir GetCurrentGenDir(const Scope* scope) {
   return GetGenDirForSourceDir(scope->settings(), scope->GetSourceDir());
 }