[tools] Add gc-nvp-to-csv.py script.

tools/gc-nvp-to-csv.py

+#!/usr/bin/env python
+#
+# Copyright 2015 the V8 project 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 is an utility for generating csv files based on GC traces produced by
+# V8 when run with flags --trace-gc --trace-gc-nvp.
+#
+# Usage: gc-nvp-to-csv.py <GC-trace-filename>
+#
+
+import sys
+import gc_nvp_common
+
+def process_trace(filename):
+  trace = gc_nvp_common.parse_gc_trace(filename)
+  if len(trace):
+    keys = trace[0].keys()
+    print ', '.join(keys)
+    for entry in trace:
+      print ', '.join(map(lambda key: str(entry[key]), keys))
+
+
+if len(sys.argv) != 2:
+  print "Usage: %s <GC-trace-filename>" % sys.argv[0]
+  sys.exit(1)
+
+process_trace(sys.argv[1])