Use WithoutPathExpansion on DictionaryValue in GN.

tools/gn/json_project_writer.cc

 // Copyright (c) 2016 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/json_project_writer.h"
 
 #include <iostream>
 
 #include "base/command_line.h"
 #include "base/json/json_writer.h"
@@ skipping 82 matching lines @@
     auto description =
         DescBuilder::DescriptionForTarget(target, "", false, false, false);
     // Outputs need to be asked for separately.
     auto outputs = DescBuilder::DescriptionForTarget(target, "source_outputs",
                                                      false, false, false);
     base::DictionaryValue* outputs_value = nullptr;
     if (outputs->GetDictionary("source_outputs", &outputs_value) &&
         !outputs_value->empty()) {
       description->MergeDictionary(outputs.get());
     }
-    targets->Set(target->label().GetUserVisibleName(default_toolchain_label),
-                 std::move(description));

[bungeman-chromium, 2016/09/23 22:26:00]

This 'Set' appears to be the one causing the issue described.

+    targets->SetWithoutPathExpansion(
+        target->label().GetUserVisibleName(default_toolchain_label),
+        std::move(description));
   }
 
   auto settings = base::MakeUnique<base::DictionaryValue>();
-  settings->SetString("root_path", build_settings->root_path_utf8());
-  settings->SetString("build_dir", build_settings->build_dir().value());
-  settings->SetString("default_toolchain",
-                      default_toolchain_label.GetUserVisibleName(false));
+  settings->SetStringWithoutPathExpansion("root_path",
+                                          build_settings->root_path_utf8());
+  settings->SetStringWithoutPathExpansion("build_dir",
+                                          build_settings->build_dir().value());
+  settings->SetStringWithoutPathExpansion(
+      "default_toolchain",
+      default_toolchain_label.GetUserVisibleName(false));
 
   auto output = base::MakeUnique<base::DictionaryValue>();
-  output->Set("targets", std::move(targets));
-  output->Set("build_settings", std::move(settings));
+  output->SetWithoutPathExpansion("targets", std::move(targets));
+  output->SetWithoutPathExpansion("build_settings", std::move(settings));
 
   std::string s;
   base::JSONWriter::WriteWithOptions(
       *output.get(), base::JSONWriter::OPTIONS_PRETTY_PRINT, &s);
   return s;
 }
 
 bool InvokePython(const BuildSettings* build_settings,
                   const base::FilePath& python_script_path,
                   const std::string& python_script_extra_args,
@@ skipping 82 matching lines @@
         script_file = SourceFile(exec_script);
       }
       base::FilePath script_path = build_settings->GetFullPath(script_file);
       return InvokePython(build_settings, script_path, exec_script_extra_args,
                           output_path, quiet, err);
     }
   }
 
   return true;
 }