gn: Support build directories outside the source tree.

tools/gn/visibility.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/visibility.h"
 
 #include "base/strings/string_piece.h"
 #include "base/strings/string_util.h"
 #include "tools/gn/err.h"
 #include "tools/gn/filesystem_utils.h"
 #include "tools/gn/item.h"
 #include "tools/gn/label.h"
 #include "tools/gn/scope.h"
 #include "tools/gn/value.h"
 #include "tools/gn/variables.h"
 
 Visibility::Visibility() {
 }
 
 Visibility::~Visibility() {
 }
 
-bool Visibility::Set(const SourceDir& current_dir,
+bool Visibility::Set(const base::FilePath& source_root,
+                     const SourceDir& current_dir,
                      const Value& value,
                      Err* err) {
   patterns_.clear();
 
   if (!value.VerifyTypeIs(Value::LIST, err)) {
     CHECK(err->has_error());
     return false;
   }
 
   for (const auto& item : value.list_value()) {
-    patterns_.push_back(LabelPattern::GetPattern(current_dir, item, err));
+    patterns_.push_back(LabelPattern::GetPattern(source_root, current_dir,
+                                                 item, err));
     if (err->has_error())
       return false;
   }
   return true;
 }
 
 void Visibility::SetPublic() {
   patterns_.clear();
   patterns_.push_back(
       LabelPattern(LabelPattern::RECURSIVE_DIRECTORY, SourceDir(),
@@ skipping 51 matching lines @@
         to->visibility().Describe(0, true));
     return false;
   }
   return true;
 }
 
 // static
 bool Visibility::FillItemVisibility(Item* item, Scope* scope, Err* err) {
   const Value* vis_value = scope->GetValue(variables::kVisibility, true);
   if (vis_value)
-    item->visibility().Set(scope->GetSourceDir(), *vis_value, err);
+    item->visibility().Set(scope->settings()->build_settings()->root_path(),
+                           scope->GetSourceDir(), *vis_value, err);
   else  // Default to public.
     item->visibility().SetPublic();
   return !err->has_error();
 }