Use Systrace tracing controller in profile_chrome

systrace/bin/adb_profile_chrome_startup

Index: systrace/bin/adb_profile_chrome_startup
diff --git a/systrace/bin/adb_profile_chrome_startup b/systrace/bin/adb_profile_chrome_startup
index 80a266bfd2272c735466acbaed728a8b6284e2c1..016f8caf17996b1b580b8c357015fa11bed5c6ed 100755
--- a/systrace/bin/adb_profile_chrome_startup
+++ b/systrace/bin/adb_profile_chrome_startup
@@ -26,6 +26,9 @@ sys.path.append(os.path.join(_CATAPULT_DIR, 'devil'))
 from devil.android import device_utils
 
 
+_DEFAULT_CHROME_CATEGORIES = '_DEFAULT_CHROME_CATEGORIES'
+
+
 def _CreateOptionParser():
   parser = optparse.OptionParser(description='Record about://tracing profiles '
                                  'from Android browsers startup, combined with '
@@ -45,7 +48,7 @@ def _CreateOptionParser():
                     'with gzip. ', action='store_true')
   parser.add_option('-t', '--time', help='Stops tracing after N seconds, 0 to '
                     'manually stop (startup trace ends after at most 5s).',
-                    default=5, metavar='N', type='int')
+                    default=5, metavar='N', type='int', dest='trace_time')
 
   parser.add_option_group(chrome_startup_tracing_agent.add_options(parser))
   parser.add_option_group(atrace_tracing_agent.add_options(parser))
@@ -68,29 +71,39 @@ def main():
   device = devices[0]
   package_info = profiler.GetSupportedBrowsers()[options.browser]
 
+  options.chrome_startup = True

[Sami, 2016/09/01 12:15:59]

Why are we overriding the options set by the user here?

[washingtonp, 2016/09/01 17:44:41]

adb_profile_chrome_startup does not provide the user with all of the
command line options that adb_profile_chrome and systrace provide.
However, these 3 clients share the same underlying tracing controller,
which expects some value (even if it is None) in the options
object it is passed. There are two solutions here:

1) Set these options that do not appear to the user when running
adb_profile_chrome_startup to None / another default value here
(what is currently being done)

or 

2) In each Get*Config() function in the agents, check if each
option in the option object exists, and if not, create it and set
it to None.

Would you like me to move to this second design? I can see the benefits
of this small design change, as it takes the burden away from the client
(for example adb_profile_chrome_startup) that does not care about
irrelevant options. I am actually leaning towards this but wondering
what others think.

[Sami, 2016/09/02 12:57:42]

My worry is that in 1) the list will quickly get out of date and in 2) we need
to add lots of boilerplate that can have typos.

I wonder if we could do something where the list of agents can be configured
dynamically instead of being static? adb_profile_chrome_startup would then
override the list of agents to the ones it supports and all others would just
use the default set minus the startup agent. WDYT?

[washingtonp, 2016/09/02 20:10:27]

I like that idea, and have implemented it in the most recent
code patch. LMK if this is what you had in mind.

+  options.device = device
+  options.package_info = package_info
+  options.ring_buffer = False
+  options.trace_memory = False
+  options.trace_cc = None
+  options.trace_frame_viewer = None
+  options.trace_ubercompositor = None
+  options.trace_gpu = None
+  options.trace_flow = None
+  options.trace_scheduler = None
+  options.ddms = None
+  options.perf_categories = None
+  options.list_categories = None
+  options.link_assets = None
+  options.asset_dir = None
+  options.timeout = None
+  options.collection_timeout = None
+  options.device_serial_number = device
+  options.target = None
+  options.chrome_categories = _DEFAULT_CHROME_CATEGORIES
+  if options.output_file:
+    options.output_file = os.path.expanduser(options.output_file)
+
   if options.atrace_categories in ['list', 'help']:
     ui.PrintMessage('\n'.join(
         atrace_tracing_agent.AtraceAgent.GetCategories(device)))
     return 0
-  atrace_categories = (options.atrace_categories.split(',')
-                         if options.atrace_categories else [])
-  enabled_agents = []
-  # Enable the atrace and chrome agents. The atrace agent should go
-  # first because otherwise the resulting traces miss early atrace data.
-  if atrace_categories:
-    enabled_agents.append(atrace_tracing_agent.AtraceAgent(
-        device, atrace_categories, False))
-  enabled_agents.append(
-      chrome_startup_tracing_agent.ChromeStartupTracingAgent(
-          device, package_info, options.cold, options.url))
-  if options.output:
-    options.output = os.path.expanduser(options.output)
   result = profiler.CaptureProfile(options,
-                                   enabled_agents,
-                                   options.time,
-                                   output=options.output,
+                                   options.trace_time,
+                                   output=options.output_file,
                                    compress=options.compress,
-                                   write_json=options.json)
+                                   write_json=options.write_json)
   if options.view:
     if sys.platform == 'darwin':
       os.system('/usr/bin/open %s' % os.path.abspath(result))