[perf] Add speedometer-ignition benchmark

tools/perf/benchmarks/v8_helper.py

Index: tools/perf/benchmarks/v8_helper.py
diff --git a/tools/perf/benchmarks/v8_helper.py b/tools/perf/benchmarks/v8_helper.py
new file mode 100644
index 0000000000000000000000000000000000000000..27df3d4264bce79fb3a4f1b07e7f34f09c109d0c
--- /dev/null
+++ b/tools/perf/benchmarks/v8_helper.py
@@ -0,0 +1,17 @@
+# Copyright 2016 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.
+
+import shlex
+
+
+def EnableIgnition(options):
+  existing_js_flags = []
+  for extra_arg in options.extra_browser_args:
+    if extra_arg.startswith('--js-flags='):
+      existing_js_flags.extend(shlex.split(extra_arg[len('--js-flags='):]))
+  options.AppendExtraBrowserArgs([
+      # This overrides any existing --js-flags, hence we have to include the
+      # previous flags as well.
+      '--js-flags=--ignition %s' % (' '.join(existing_js_flags))
+  ])