Support startup performance tests on Galaxy S3

build/android/pylib/flag_changer.py

 # Copyright (c) 2012 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 constants
 import traceback
 import warnings
 
 
 # Location where chrome reads command line flags from
 CHROME_COMMAND_FILE = '/data/local/chrome-command-line'
+CHROME_TEMP_COMMAND_FILE='/sdcard/chrome-command-line-temp'

[bulach, 2013/01/15 09:51:01]

I guess "sdcard" should be "$EXTERNAL_STORAGE"

 
 class FlagChanger(object):
   """Changes the flags Chrome runs with.
 
   There are two different use cases for this file:
   * Flags are permanently set by calling Set().
   * Flags can be temporarily set for a particular set of unit tests.  These
     tests should call Restore() to revert the flags to their original state
     once the tests have completed.
   """
@@ skipping 60 matching lines @@
   def Restore(self):
     """Restores the flags to their original state."""
     self._current_flags = self._TokenizeFlags(self._orig_line)
     self._UpdateCommandLineFile()
 
   def _UpdateCommandLineFile(self):
     """Writes out the command line to the file, or removes it if empty."""
     print "Current flags: ", self._current_flags
 
     if self._current_flags:
-      self._android_cmd.SetFileContents(CHROME_COMMAND_FILE,
+      # The command file is protected, so we have to go via a temp file
+      self._android_cmd.SetFileContents(CHROME_TEMP_COMMAND_FILE,
                                         'chrome ' +
                                         ' '.join(self._current_flags))
+      self._android_cmd.RunShellCommand('su -c dd if=' +
+                                        CHROME_TEMP_COMMAND_FILE +
+                                        ' of=' + CHROME_COMMAND_FILE)
+      self._android_cmd.RunShellCommand('su -c chmod 777 ' +
+                                        CHROME_COMMAND_FILE)
+      self._android_cmd.RunShellCommand('rm ' + CHROME_TEMP_COMMAND_FILE)

[bulach, 2013/01/15 09:51:01]

we could potentially generate a shell script for these three commands and source
it, but I don't think it'd be any more readable...

     else:
-      self._android_cmd.RunShellCommand('rm ' + CHROME_COMMAND_FILE)
+      self._android_cmd.RunShellCommand('su -c rm ' + CHROME_COMMAND_FILE)
 
   def _TokenizeFlags(self, line):
     """Changes the string containing the command line into a list of flags.
 
     Follows similar logic to CommandLine.java::tokenizeQuotedArguments:
     * Flags are split using whitespace, unless the whitespace is within a
       pair of quotation marks.
     * Unlike the Java version, we keep the quotation marks around switch
       values since we need them to re-create the file when new flags are
       appended.
@@ skipping 28 matching lines @@
 
     # Tack on the last flag.
     if not current_flag:
       if within_quotations:
         warnings.warn("Unterminated quoted string: " + current_flag)
     else:
       tokenized_flags.append(current_flag)
 
     # Return everything but the program name.
     return tokenized_flags[1:]