Use WithoutPathExpansion on DictionaryValue in GN.

tools/gn/json_project_writer.cc

Index: tools/gn/json_project_writer.cc
diff --git a/tools/gn/json_project_writer.cc b/tools/gn/json_project_writer.cc
index 67c21ee2d7f68eebeb79abcf6945373d1fd80eed..44576cdcdd608d57b0b64c994b5c80e4f69552da 100644
--- a/tools/gn/json_project_writer.cc
+++ b/tools/gn/json_project_writer.cc
@@ -100,19 +100,23 @@ std::string RenderJSON(const BuildSettings* build_settings,
         !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(