Update from https://crrev.com/329939

tools/clang/scripts/blink_gc_plugin_flags.sh

 #!/usr/bin/env bash
 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-# This script returns the flags that should be passed to clang.
-
-SRC_DIR=$(cd $(dirname $0)/../../.. && echo $PWD)
-CLANG_LIB_PATH=$SRC_DIR/third_party/llvm-build/Release+Asserts/lib
-
-if uname -s | grep -q Darwin; then
-  LIBSUFFIX=dylib
-else
-  LIBSUFFIX=so
-fi
-
-FLAGS=""
-PREFIX="-Xclang -plugin-arg-blink-gc-plugin -Xclang"
-for arg in "$@"; do
-  if [[ "$arg" = "enable-oilpan=1" ]]; then
-    FLAGS="$FLAGS $PREFIX enable-oilpan"
-  elif [[ "$arg" = "dump-graph=1" ]]; then
-    FLAGS="$FLAGS $PREFIX dump-graph"
-  elif [[ "$arg" = "warn-raw-ptr=1" ]]; then
-    FLAGS="$FLAGS $PREFIX warn-raw-ptr"
-  elif [[ "$arg" = "warn-unneeded-finalizer=1" ]]; then
-    FLAGS="$FLAGS $PREFIX warn-unneeded-finalizer"
-  elif [[ "$arg" = custom_clang_lib_path=* ]]; then
-    CLANG_LIB_PATH="$(cd "${arg#*=}" && echo $PWD)"
-  fi
-done
-
-echo -Xclang -load -Xclang \"$CLANG_LIB_PATH/libBlinkGCPlugin.$LIBSUFFIX\" \
-  -Xclang -add-plugin -Xclang blink-gc-plugin $FLAGS
+# TODO(thakis): Remove this script once Source/config.gyp refers the the .py
+# file.
+THIS_DIR="$(dirname "${0}")"
+ABS_THIS_DIR="${PWD}/${THIS_DIR}"
+exec python "${ABS_THIS_DIR}/blink_gc_plugin_flags.py" "$@"