Enables (temporarily) adb trace for sharded perf tests.

third_party/android_testrunner/run_command.py

 #!/usr/bin/python2.4
 #
 #
 # Copyright 2007, The Android Open Source Project
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
 #
 #     http://www.apache.org/licenses/LICENSE-2.0
 #
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
 # System imports
 import os
 import signal
 import subprocess
 import tempfile
 import threading
 import time
+import sys
 
 # local imports
 import errors
 import logger
 
 _abort_on_error = False
 
 def SetAbortOnError(abort=True):
   """Sets behavior of RunCommand to throw AbortError if command process returns
   a negative error code"""
@@ skipping 51 matching lines @@
 
   if return_output:
     output_dest = tempfile.TemporaryFile(bufsize=0)
   else:
     # None means direct to stdout
     output_dest = None
   if stdin_input:
     stdin_dest = subprocess.PIPE
   else:
     stdin_dest = None
+  stderr_dest = subprocess.STDOUT
+  if os.environ.get('ADB_TRACE'):
+    stderr_dest = sys.stdout
   pipe = subprocess.Popen(
       cmd,
       executable='/bin/bash',
       stdin=stdin_dest,
       stdout=output_dest,
-      stderr=subprocess.STDOUT,
+      stderr=stderr_dest,
       shell=True, close_fds=True,
       preexec_fn=lambda: signal.signal(signal.SIGPIPE, signal.SIG_DFL))
 
   def Run():
     global error_occurred
     try:
       pipe.communicate(input=stdin_input)
       output = None
       if return_output:
         output_dest.seek(0)
@@ skipping 71 matching lines @@
 def HasValgrind():
   """Check that /usr/bin/valgrind exists.
 
   We look for the fullpath to avoid picking up 'alternative' valgrind
   on the system.
 
   Returns:
     True if a system valgrind was found.
   """
   return os.path.exists("/usr/bin/valgrind")