IDL: Add build target for IDL dictionary impl generation in core

Source/core/core.gypi

Index: Source/core/core.gypi
diff --git a/Source/core/core.gypi b/Source/core/core.gypi
index b1eec4ef2343d344d21fbcff9ee27a7cb80f2edc..d3fb51123b4dc09f1f1f5d229c61b6fc21e487a6 100644
--- a/Source/core/core.gypi
+++ b/Source/core/core.gypi
@@ -488,6 +488,9 @@
             'workers/AbstractWorker.idl',
             'xml/DocumentXPathEvaluator.idl',
         ],
+        'core_dictionary_idl_files': [
+            'css/FontFaceDescriptors.idl',
+        ],
         # interfaces that inherit from Event, including Event itself
         'core_event_idl_files': [
             'css/CSSFontFaceLoadEvent.idl',
@@ -3321,6 +3324,10 @@
           '<(blink_core_output_dir)/InternalRuntimeFlags.idl',
           '<(blink_core_output_dir)/InternalSettingsGenerated.idl',
         ],
+        'generated_core_dictionary_files': [
+          '<(blink_core_output_dir)/css/FontFaceDescriptors.cpp',
+          '<(blink_core_output_dir)/css/FontFaceDescriptors.h',
+        ],
         'webcore_testing_files': [
             '<(blink_core_output_dir)/InternalSettingsGenerated.cpp',
             '<(blink_core_output_dir)/InternalSettingsGenerated.h',