Add more git tracing.

This CL adds more perf tracing to `git fetch` from bot_update.py and
git_cache.py

Change-Id: I9b69c60b6c81fc0c5f23f82fcc889b4d45a27556
Recipe-Nontrivial-Roll: build_limited_scripts_slave
Recipe-Nontrivial-Roll: build
Recipe-Nontrivial-Roll: infra
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1888433Reviewed-by: Andrii Shyshkalov <tandrii@google.com>
Commit-Queue: Erik Chen <erikchen@chromium.org>
Auto-Submit: Erik Chen <erikchen@chromium.org>

git_cache.py

@@ -552,14 +552,6 @@ class Mirror(object):
       spec = spec.decode()
       try:
         self.print('Fetching %s' % spec)
-        env = os.environ.copy()
-        env.update({
-            'GIT_TRACE_PACKET': '1',
-            'GIT_TR2_EVENT': '1',
-            'GIT_TRACE2_EVENT': '1',
-            'GIT_TRACE_CURL': '1',
-            'GIT_TRACE_CURL_NO_DATA': '1'
-        })
         # Only print first 30000 packets. We can use nonlocal keyword once we
         # switch to python 3.
         packet_count = [0]
@@ -578,7 +570,6 @@ class Mirror(object):
               fetch_cmd + [spec],
               cwd=rundir,
               retry=True,
-              env=env,
               filter_fn=FilterPacket)
       except subprocess.CalledProcessError:
         if spec == '+refs/heads/*:refs/heads/*':

recipes/recipe_modules/bot_update/resources/bot_update.py

@@ -666,6 +666,11 @@ def _git_checkout(sln, sln_dir, revisions, refs, git_cache_dir, cleanup_dir):
     env = {
         'GIT_TRACE': 'true',
         'GIT_TRACE_PERFORMANCE': 'true',
+        'GIT_TRACE_PACKET': '1',
+        'GIT_TRACE2_EVENT': '1',
+        'GIT_TRACE_CURL': '1',
+        'GIT_TRACE_CURL_NO_DATA': '1',
+        'INFRA_GIT_WRAPPER_TRACE': '1',
     }
 
   # Step 1: populate/refresh cache, if necessary.
@@ -723,11 +728,11 @@ def _git_checkout(sln, sln_dir, revisions, refs, git_cache_dir, cleanup_dir):
       else:
         _git_disable_gc(sln_dir)
         git('remote', 'set-url', 'origin', mirror_dir, cwd=sln_dir)
-        git('fetch', 'origin', cwd=sln_dir)
+        git('fetch', 'origin', cwd=sln_dir, env=env)
       git('remote', 'set-url', '--push', 'origin', url, cwd=sln_dir)
       for ref in refs:
         refspec = '%s:%s' % (ref, ref.lstrip('+'))
-        git('fetch', 'origin', refspec, cwd=sln_dir)
+        git('fetch', 'origin', refspec, cwd=sln_dir, env=env)
 
       # Windows sometimes has trouble deleting files.
       # This can make git commands that rely on locks fail.