Remove cwd logic from generate_perf_json.py

Remove cwd logic from generate_perf_json.py

This patch refactors generate_perf_json.py to avoid using cwd logic.
File paths are now relative to src which is derived relative to the
script location.

BUG=667435
Committed: https://crrev.com/ba78be88a98b57c9e4195c59a26156a4c3cf4765
Cr-Commit-Position: refs/heads/master@{#436208}

[alancutter (OOO until 2018), 2016-12-01 04:40:01]

alancutter@chromium.org changed reviewers:
+ dtu@chromium.org

[dtu, 2016-12-03 00:45:09]

The CQ bit was checked by dtu@chromium.org

[dtu, 2016-12-03 00:45:10]

lgtm

lovely, thanks! lgtm

[commit-bot: I haz the power, 2016-12-03 00:46:02]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-12-03 02:27:41]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-12-03 02:27:42]

Failed to apply patch for tools/perf/generate_perf_json.py:
While running git apply --index -p1;
  error: patch failed: tools/perf/generate_perf_json.py:537
  error: tools/perf/generate_perf_json.py: patch does not apply

Patch:       tools/perf/generate_perf_json.py
Index: tools/perf/generate_perf_json.py
diff --git a/tools/perf/generate_perf_json.py b/tools/perf/generate_perf_json.py
index
d75c7d8985ced36ea38300787b96eab49da1c576..c0c637fe8fcc2db8ffc1b938c6ad2a12a6f09526
100755
--- a/tools/perf/generate_perf_json.py
+++ b/tools/perf/generate_perf_json.py
@@ -537,7 +537,7 @@ BENCHMARK_NAME_BLACKLIST = [
 
 
 def current_benchmarks(use_whitelist):
-  benchmarks_dir = os.path.join(os.getcwd(), 'benchmarks')
+  benchmarks_dir = os.path.join(src_dir(), 'tools', 'perf', 'benchmarks')
   top_level_dir = os.path.dirname(benchmarks_dir)
 
   all_benchmarks = discover.DiscoverClasses(
@@ -564,8 +564,10 @@ def get_sorted_benchmark_list_by_time(all_benchmarks):
   runtime_list = []
   benchmark_avgs = {}
   new_benchmarks = []
+  timing_file_path = os.path.join(src_dir(), 'tools', 'perf',
+      'desktop_benchmark_avg_times.json')
   # Load in the avg times as calculated on Nov 1st, 2016
-  with open('desktop_benchmark_avg_times.json') as f:
+  with open(timing_file_path) as f:
     benchmark_avgs = json.load(f)
 
   for benchmark in all_benchmarks:
@@ -656,19 +658,16 @@ def generate_all_tests(waterfall):
   tests['AAAAA2 See //tools/perf/generate_perf_json.py to make changes'] = {}
   filename = '%s.json' % waterfall['name']
 
-  src_dir = os.path.dirname(os.path.dirname(os.getcwd()))
-
-  with open(os.path.join(src_dir, 'testing', 'buildbot', filename), 'w') as fp:
+  buildbot_dir = os.path.join(src_dir(), 'testing', 'buildbot')
+  with open(os.path.join(buildbot_dir, filename), 'w') as fp:
     json.dump(tests, fp, indent=2, separators=(',', ': '), sort_keys=True)
     fp.write('\n')
 
-def chdir_to_parent_directory():
-  parent_directory = os.path.dirname(os.path.abspath(__file__))
-  os.chdir(parent_directory)
+def src_dir():
+  file_path = os.path.abspath(__file__)
+  return os.path.dirname(os.path.dirname(os.path.dirname(file_path)))
 
 def main():
-  chdir_to_parent_directory()
-
   waterfall = get_waterfall_config()
   waterfall['name'] = 'chromium.perf'
   fyi_waterfall = get_fyi_waterfall_config()

[alancutter (OOO until 2018), 2016-12-04 23:07:23]

The CQ bit was checked by alancutter@chromium.org

[alancutter (OOO until 2018), 2016-12-04 23:07:23]

The patchset sent to the CQ was uploaded after l-g-t-m from dtu@chromium.org
Link to the patchset: https://codereview.chromium.org/2542073003/#ps20001
(title: "Rebased")

[commit-bot: I haz the power, 2016-12-04 23:07:30]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-12-05 00:02:08]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1480892843211060,
"parent_rev": "95f1fc16371d447273cd47a71d6e68a7642a3312", "commit_rev":
"76630420d64b6975cb7fc6a47999efea231557fe"}

[commit-bot: I haz the power, 2016-12-05 00:02:32]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-12-05 00:04:47]

Description was changed from

==========
Remove cwd logic from generate_perf_json.py

This patch refactors generate_perf_json.py to avoid using cwd logic.
File paths are now relative to src which is derived relative to the
script location.

BUG=667435
==========

to

==========
Remove cwd logic from generate_perf_json.py

This patch refactors generate_perf_json.py to avoid using cwd logic.
File paths are now relative to src which is derived relative to the
script location.

BUG=667435

Committed: https://crrev.com/ba78be88a98b57c9e4195c59a26156a4c3cf4765
Cr-Commit-Position: refs/heads/master@{#436208}
==========

[commit-bot: I haz the power, 2016-12-05 00:04:50]

Patchset 2 (id:??) landed as
https://crrev.com/ba78be88a98b57c9e4195c59a26156a4c3cf4765
Cr-Commit-Position: refs/heads/master@{#436208}