gn2bp: Move response file to gn_utils

* This is a GN-specific flag that should live in gn_utils as it might be used in the future when converting to Bazel.

Test: update_results.sh
Change-Id: If870f757cf3ee57a00c571947a7ffea18a7db55d

tools/gn2bp/gn_utils.py

@@ -52,6 +52,8 @@ ODR_VIOLATION_IGNORE_TARGETS = {
 ARCH_REGEX = r'(android_x86_64|android_x86|android_arm|android_arm64|host)'
 DEX_REGEX = '.*__dex__%s$' % ARCH_REGEX
 COMPILE_JAVA_REGEX = '.*__compile_java__%s$' % ARCH_REGEX
+RESPONSE_FILE = '{{response_file_name}}'
+
 def repo_root():
   """Returns an absolute path to the repository root."""
   return os.path.join(