Add script to compare performance of two versions of pdfium.

Run from the pdfium root:

$ testing/tools/safetynet_compare.py testing
This compares the current branch with and without local changes.

$ testing/tools/safetynet_compare.py testing/corpus --branch-before x
This compares the current branch + local changes against branch x.
It runs only the corpus tests.

$ testing/tools/safetynet_compare.py testing --branch-before x
    --branch-after y --build-dir=~/output_compare
This compares branch x and branch y. x and y can be revision hashes.
The callgrind.out files of cases with significant changes will be
created in ~/output_compare.

$ testing/tools/safetynet_compare.py -h
Print all options.

Change-Id: I43aaf5fe890745db611fb3bc00a656ef799fdfef
Reviewed-on: https://pdfium-review.googlesource.com/7390
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Henrique Nakashima <hnakashima@chromium.org>

1 files changed, 12 insertions, 0 deletions

diff --git a/testing/tools/common.py b/testing/tools/common.py
index b6e4a7d62e..c3bc2181f4 100755
--- a/testing/tools/common.py
+++ b/testing/tools/common.py
@@ -5,6 +5,7 @@
 
 import glob
 import os
+import re
 import subprocess
 import sys
 
@@ -96,3 +97,14 @@ class DirectoryFinder:
     if other_components:
       result = os.path.join(result, other_components)
     return result
+
+
+def GetBooleanGnArg(arg_name, build_dir):
+    '''Extract the value of a boolean flag in args.gn'''
+    cwd = os.getcwd()
+    os.chdir(build_dir)
+    gn_args_output = subprocess.check_output(
+        ['gn', 'args', '.', '--list=%s' % arg_name, '--short'])
+    os.chdir(cwd)
+    arg_match_output = re.search('%s = (.*)' % arg_name, gn_args_output).group(1)
+    return arg_match_output == 'true'