[DO NOT COMMIT] Refactor systrace to support new clock sync design

devil/devil/android/device_utils.py

Index: devil/devil/android/device_utils.py
diff --git a/devil/devil/android/device_utils.py b/devil/devil/android/device_utils.py
index ef2f08ac0f0cafad01fbb89bb0d02e2f1d46a155..7b838406c42808d31ebcabe911fea1b470dc882c 100644
--- a/devil/devil/android/device_utils.py
+++ b/devil/devil/android/device_utils.py
@@ -714,7 +714,7 @@ class DeviceUtils(object):
   @decorators.WithTimeoutAndRetriesFromInstance()
   def RunShellCommand(self, cmd, check_return=False, cwd=None, env=None,
                       as_root=False, single_line=False, large_output=False,
-                      timeout=None, retries=None):
+                      timeout=None, retries=None, split_lines=True):
     """Run an ADB shell command.
 
     The command to run |cmd| should be a sequence of program arguments or else
@@ -751,6 +751,7 @@ class DeviceUtils(object):
         this large output will be truncated.
       timeout: timeout in seconds
       retries: number of retries
+      split_lines: Whether to split the output into a list of lines.
 
     Returns:
       If single_line is False, the output of the command as a list of lines,
@@ -825,9 +826,12 @@ class DeviceUtils(object):
       # "su -c sh -c" allows using shell features in |cmd|
       cmd = self._Su('sh -c %s' % cmd_helper.SingleQuote(cmd))
 
-    output = handle_large_output(cmd, large_output).splitlines()
+    output = handle_large_output(cmd, large_output)
 
-    if single_line:
+    if split_lines:
+      output = output.splitlines()
+
+    if split_lines and single_line:
       if not output:
         return ''
       elif len(output) == 1: