Fix cmd line args override in common.py

tools/chrome_proxy/webdriver/common.py

 # Copyright 2016 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 argparse
 import json
 import os
 import shlex
 import sys
 import time
@@ skipping 59 matching lines @@
 
   def __enter__(self):
     return self
 
   def __exit__(self, exc_type, exc_value, tb):
     if self._driver:
       self._StopDriver()
 
   def _OverrideChromeArgs(self):
     """
-    Overrides any given flags in the code with those given on the command line.
+    Overrides any given arguments in the code with those given on the command
+    line. Arguments that need to be overridden may contain different values for
+    a flag given in the code. In that case, check by the flag whether to
+    override the argument.
     """
+    def GetDictKey(argument):
+      return argument.split('=', 1)[0]
     if self._flags.browser_args and len(self._flags.browser_args) > 0:
-      for arg in shlex.split(self._flags.browser_args):
-        self._chrome_args.add(arg)
+      # Build a dict of flags mapped to the whole argument.
+      original_args = {}
+      for arg in self._chrome_args:
+          original_args[GetDictKey(arg)] = arg
+      # Override by flag.
+      for override_arg in shlex.split(self._flags.browser_args[0]):
+        arg_key = GetDictKey(override_arg)
+        if arg_key in original_args:
+          self._chrome_args.remove(original_args[arg_key])
+        self._chrome_args.add(override_arg)
 
   def _StartDriver(self):
     """
     Parses the flags to pass to Chromium, then starts the ChromeDriver.
     """
+    self._OverrideChromeArgs()
     options = Options()
     for arg in self._chrome_args:
       options.add_argument(arg)
     capabilities = {'loggingPrefs': {'performance': 'INFO'}}
     if self._flags.chrome_exec:
       capabilities['chrome.binary'] = self._flags.chrome_exec
     driver = webdriver.Chrome(executable_path=self._flags.chrome_driver[0],
       chrome_options=options, desired_capabilities=capabilities)
     driver.command_executor._commands.update({
       'getAvailableLogTypes': ('GET', '/session/$sessionId/log/types'),
@@ skipping 104 matching lines @@
   def Fail(self, msg):
     sys.stderr.write("**************************************\n")
     sys.stderr.write("**************************************\n")
     sys.stderr.write("**                                  **\n")
     sys.stderr.write("**          TEST FAILURE            **\n")
     sys.stderr.write("**                                  **\n")
     sys.stderr.write("**************************************\n")
     sys.stderr.write("**************************************\n")
     sys.stderr.write(msg, '\n')
     sys.exit(1)