Re-land r406064 "[GN] Add JSON project writer".

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/memory/ptr_util.h"
 #include "base/strings/string_piece.h"
 #include "base/strings/string_util.h"
+#include "base/values.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() {
 }
@@ skipping 57 matching lines @@
   }
 
   for (const auto& pattern : patterns_)
     result += inner_indent_string + pattern.Describe() + "\n";
 
   if (include_brackets)
     result += outer_indent_string + "]\n";
   return result;
 }
 
+std::unique_ptr<base::Value> Visibility::AsValue() const {
+  auto* res = new base::ListValue();
+  for (const auto& pattern : patterns_)
+    res->AppendString(pattern.Describe());
+
+  return WrapUnique(res);
+}
+
 // static
 bool Visibility::CheckItemVisibility(const Item* from,
                                      const Item* to,
                                      Err* err) {
   if (!to->visibility().CanSeeMe(from->label())) {
     std::string to_label = to->label().GetUserVisibleName(false);
     *err = Err(from->defined_from(), "Dependency not allowed.",
         "The item " + from->label().GetUserVisibleName(false) + "\n"
         "can not depend on " + to_label + "\n"
         "because it is not in " + to_label + "'s visibility list: " +
-        to->visibility().Describe(0, true));
+                   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);
   else  // Default to public.
     item->visibility().SetPublic();
   return !err->has_error();
 }