GN: Make file/dir resolving return errors.

tools/gn/value_extractors.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/value_extractors.h"
 
 #include "tools/gn/build_settings.h"
 #include "tools/gn/err.h"
 #include "tools/gn/label.h"
 #include "tools/gn/source_dir.h"
@@ skipping 47 matching lines @@
   return true;
 }
 
 struct RelativeFileConverter {
   RelativeFileConverter(const BuildSettings* build_settings_in,
                         const SourceDir& current_dir_in)
       : build_settings(build_settings_in),
         current_dir(current_dir_in) {
   }
   bool operator()(const Value& v, SourceFile* out, Err* err) const {
-    if (!v.VerifyTypeIs(Value::STRING, err))
-      return false;
-    *out = current_dir.ResolveRelativeFile(v.string_value(),
+    *out = current_dir.ResolveRelativeFile(v, err,
                                            build_settings->root_path_utf8());
-    return true;
+    return !err->has_error();
   }
   const BuildSettings* build_settings;
   const SourceDir& current_dir;
 };
 
 struct RelativeDirConverter {
   RelativeDirConverter(const BuildSettings* build_settings_in,
                        const SourceDir& current_dir_in)
       : build_settings(build_settings_in),
         current_dir(current_dir_in) {
   }
   bool operator()(const Value& v, SourceDir* out, Err* err) const {
-    if (!v.VerifyTypeIs(Value::STRING, err))
-      return false;
-    *out = current_dir.ResolveRelativeDir(v.string_value(),
+    *out = current_dir.ResolveRelativeDir(v, err,
                                           build_settings->root_path_utf8());
     return true;
   }
   const BuildSettings* build_settings;
   const SourceDir& current_dir;
 };
 
 // Fills in a label.
 template<typename T> struct LabelResolver {
   LabelResolver(const SourceDir& current_dir_in,
@@ skipping 103 matching lines @@
 }
 
 bool ExtractRelativeFile(const BuildSettings* build_settings,
                          const Value& value,
                          const SourceDir& current_dir,
                          SourceFile* file,
                          Err* err) {
   RelativeFileConverter converter(build_settings, current_dir);
   return converter(value, file, err);
 }