adb_profile_chrome: Add perf profiler

build/android/chrome_profiler/profiler.py

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import gzip
 import os
 import shutil
 import sys
 import zipfile
 
@@ skipping 35 matching lines @@
     controller.StartTracing(interval)
 
 
 def _StopTracing(controllers):
   for controller in controllers:
     controller.StopTracing()
 
 
 def _PullTraces(controllers, output, compress, write_json):
   ui.PrintMessage('Downloading...', eol='')
-  trace_files = []
-  for controller in controllers:
-    trace_files.append(controller.PullTrace())
+  trace_files = [controller.PullTrace() for controller in controllers]
 
   if not write_json:
     html_file = os.path.splitext(trace_files[0])[0] + '.html'
     _PackageTracesAsHtml(trace_files, html_file)
     trace_files = [html_file]
 
   if compress and len(trace_files) == 1:
     result = output or trace_files[0] + '.gz'
     _CompressFile(trace_files[0], result)
   elif len(trace_files) > 1:
@@ skipping 52 matching lines @@
     else:
       ui.PrintMessage('Capturing %s. Press Enter to stop...' % \
           trace_type, eol='')
       raw_input()
   finally:
     _StopTracing(controllers)
   if interval:
     ui.PrintMessage('done')
 
   return _PullTraces(controllers, output, compress, write_json)