[Android] Add an option to view the tracing record categories when running from python script.

build/android/adb_profile_chrome.py

Index: build/android/adb_profile_chrome.py
diff --git a/build/android/adb_profile_chrome.py b/build/android/adb_profile_chrome.py
index 37f250c19a2b4b9c38c0e2cb1f87cf96b4406d13..ae69ced1b55a707d032a36e5b9515da8509cab43 100755
--- a/build/android/adb_profile_chrome.py
+++ b/build/android/adb_profile_chrome.py
@@ -5,6 +5,7 @@
 # found in the LICENSE file.
 
 import gzip
+import json
 import logging
 import optparse
 import os
@@ -53,6 +54,38 @@ class ChromeTracingController(object):
   def __str__(self):
     return 'chrome trace'
 
+  @staticmethod
+  def GetCategories(device, package_info):
+    device.old_interface.BroadcastIntent(
+        package_info.package, 'GPU_PROFILER_LIST_CATEGORY')
+    try:
+      json_category_list = device.old_interface.WaitForLogMatch(
+          re.compile(r'{"traceCategoriesList(.*)'), None, timeout=5).group(0)
+
+      record_categories = []
+      disabled_by_default_categories = []
+      try:
+        json_data = json.loads(json_category_list)['traceCategoriesList']
+        for item in json_data:
+          if item.startswith('disabled-by-default'):
+            disabled_by_default_categories.append(item)
+          else:
+            record_categories.append(item)
+      except (ValueError, KeyError, TypeError):
+        logging.error('JSON format error')

[Sami, 2014/05/06 14:29:51]

I'd prefer just passing these exceptions through since if anything like this
happens it is more useful to fail noisily with a backtrace.

[r.kasibhatla, 2014/05/06 15:22:29]

Done.

+
+      _PrintMessage('Record Categories:')

[Sami, 2014/05/06 14:29:51]

Instead of printing the results here, could you return a tuple
(record_categories, disabled_by_default_categories) and print them out at the
call site? That way we can use this function for other purposes  too (e.g.,
checking that we're using valid categories).

[r.kasibhatla, 2014/05/06 15:22:29]

In the original patch, I was returning the tuple, but changed to avoid the
unnecessary creation of lists at two places. Anyways, I reverted to previous
patch logic of returning the tuple. :)

+      _PrintMessage('\n'.join(str('\t%s' % item) \

[Sami, 2014/05/06 14:29:51]

Nit: "str" is unneeded here.

[r.kasibhatla, 2014/05/06 15:22:29]

Done.

+          for item in sorted(record_categories)))
+
+      _PrintMessage('\nDisabled by Default Categories:')
+      _PrintMessage('\n'.join(str('\t%s' % item) \

[Sami, 2014/05/06 14:29:51]

Ditto.

[r.kasibhatla, 2014/05/06 15:22:29]

Done.

+          for item in sorted(disabled_by_default_categories)))
+
+    except pexpect.TIMEOUT:

[Sami, 2014/05/06 14:29:51]

Please move this try/except block immediately around WaitForLogMatch since
that's the only place where we expect to get this exception.

[r.kasibhatla, 2014/05/06 15:22:29]

Done.

+      raise RuntimeError('Performance trace category list marker not found. '
+                         'Is the correct version of the browser running?')
+
   def StartTracing(self, interval):
     self._trace_interval = interval
     self._device.old_interface.SyncLogCat()
@@ -324,7 +357,8 @@ def main():
                         'categories with comma-delimited wildcards, '
                         'e.g., "*", "cat1*,-cat1a". Omit this option to trace '
                         'Chrome\'s default categories. Chrome tracing can be '
-                        'disabled with "--categories=\'\'".',
+                        'disabled with "--categories=\'\'". Use "list" to see '
+                        'the available categories.',
                         metavar='CHROME_CATEGORIES', dest='chrome_categories',
                         default=_DEFAULT_CHROME_CATEGORIES)
   categories.add_option('-s', '--systrace', help='Capture a systrace with the '
@@ -383,6 +417,12 @@ When in doubt, just try out --trace-frame-viewer.
   if len(devices) != 1:
     parser.error('Exactly 1 device much be attached.')
   device = device_utils.DeviceUtils(devices[0])
+  package_info = _GetSupportedBrowsers()[options.browser]
+
+  if options.chrome_categories in ['list', 'help']:
+    _PrintMessage('Collecting data...', '\r')

[Sami, 2014/05/06 14:29:51]

Nit: please use eol='' to match the other functions here.

[r.kasibhatla, 2014/05/06 15:22:29]

Done.

+    ChromeTracingController.GetCategories(device, package_info)
+    return 0
 
   if options.systrace_categories in ['list', 'help']:
     _PrintMessage('\n'.join(SystraceController.GetCategories(device)))
@@ -394,7 +434,6 @@ When in doubt, just try out --trace-frame-viewer.
 
   chrome_categories = _ComputeChromeCategories(options)
   systrace_categories = _ComputeSystraceCategories(options)
-  package_info = _GetSupportedBrowsers()[options.browser]
 
   if chrome_categories and 'webview' in systrace_categories:
     logging.warning('Using the "webview" category in systrace together with '