Add FontFaceDescriptors IDL dictionary

Source/bindings/core/idl.gni

Index: Source/bindings/core/idl.gni
diff --git a/Source/bindings/core/idl.gni b/Source/bindings/core/idl.gni
index 819186bd2f15613dfc5153f6b971e085ff97d385..08319eb8018aadb36313c5040f7a971e0fdb2618 100644
--- a/Source/bindings/core/idl.gni
+++ b/Source/bindings/core/idl.gni
@@ -8,6 +8,10 @@ import("//third_party/WebKit/Source/core/core.gni")
 # Don't actually read idl.gypi since that just defines variables in terms of
 # others, which gypi_to_gn doesn't handle.
 
+core_definition_idl_files =
+  core_dictionary_idl_files +
+  core_idl_files
+
 core_testing_definition_idl_files =
   core_testing_dictionary_idl_files +
   webcore_testing_idl_files
@@ -15,13 +19,13 @@ core_testing_definition_idl_files =
 # IDL file lists; see: http://www.chromium.org/developers/web-idl-interfaces
 # Interface IDL files: generate individual bindings (includes testing)
 core_interface_idl_files =
-  core_idl_files +
+  core_definition_idl_files +
   core_testing_definition_idl_files +
   generated_webcore_testing_idl_files
 
 # Static IDL files
 core_static_interface_idl_files =
-  core_idl_files +
+  core_definition_idl_files +
   core_testing_definition_idl_files
 core_static_dependency_idl_files =
   core_dependency_idl_files +