Work on blink GN bindings

Source/platform/platform_generated.gni

Index: Source/platform/platform_generated.gni
diff --git a/Source/core/core_generated.gypi b/Source/platform/platform_generated.gni
similarity index 62%
copy from Source/core/core_generated.gypi
copy to Source/platform/platform_generated.gni
index ad60ff009b699ad462408f97fd81264244cce43f..be9f25c4efd9f4f329984712d4d20bf471d3edd9 100644
--- a/Source/core/core_generated.gypi
+++ b/Source/platform/platform_generated.gni
@@ -2,8 +2,4 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-{
-  'variables': {
-    'blink_core_output_dir': '<(SHARED_INTERMEDIATE_DIR)/blink/core',
-  },
-}
+blink_platform_output_dir = "$root_gen_dir/blink/platform"