Add ANGLE vulkan GN to gypi whitelist.

.gn

 # This file is used by the GN meta build system to find the root of the source
 # tree and to set startup options. For documentation on the values set in this
 # file, run "gn help dotfile" at the command line.
 
 # The location of the build configuration file.
 buildconfig = "//build/config/BUILDCONFIG.gn"
 
 # The secondary source root is a parallel directory tree where
 # GN build files are placed when they can not be placed directly
 # in the source tree, e.g. for third party source trees.
@@ skipping 245 matching lines @@
   "//content/test/BUILD.gn",
   "//jingle/BUILD.gn",
   "//net/BUILD.gn",
   "//printing/BUILD.gn",
   "//remoting/host/BUILD.gn",
   "//remoting/remoting_srcs.gni",
   "//remoting/remoting_version.gni",
   "//third_party/android_platform/BUILD.gn",
   "//third_party/angle/BUILD.gn",
   "//third_party/angle/src/tests/BUILD.gn",
+  "//third_party/angle/src/vulkan_support/BUILD.gn",
   "//third_party/boringssl/BUILD.gn",
   "//third_party/catapult/tracing/BUILD.gn",
   "//third_party/cld_2/BUILD.gn",
   "//third_party/google_input_tools/inputview.gni",
   "//third_party/harfbuzz-ng/BUILD.gn",
   "//third_party/libaddressinput/BUILD.gn",
   "//third_party/openh264/BUILD.gn",
   "//third_party/skia/gn/shared_sources.gni",
   "//third_party/WebKit/Source/bindings/bindings.gni",
   "//third_party/WebKit/Source/bindings/scripts/scripts.gni",
   "//third_party/WebKit/Source/config.gni",
   "//third_party/WebKit/Source/core/core.gni",
   "//third_party/WebKit/Source/modules/modules.gni",
   "//third_party/WebKit/Source/web/BUILD.gn",
   "//tools/gn/BUILD.gn",
   "//ui/accessibility/BUILD.gn",
   "//ui/gfx/BUILD.gn",
   "//v8/test/cctest/BUILD.gn",
   "//v8/test/unittests/BUILD.gn",
 
   # Not gypi-to-gn.
   "//google_apis/BUILD.gn",
 ]