[chromedriver] Quit Chrome before cleaning up temporary directories

BUG=
NOTRY=true
TBR=stgao@chromium.org

Review URL: https://codereview.chromium.org/671433005

Cr-Commit-Position: refs/heads/master@{#300695}

chrome/test/chromedriver/test/run_py_tests.py

@@ -105,6 +105,7 @@ _ANDROID_NEGATIVE_FILTER['chrome'] = (
         'ChromeSwitchesCapabilityTest.*',
         'ChromeExtensionsCapabilityTest.*',
         'MobileEmulationCapabilityTest.*',
+        'ChromeDownloadDirTest.*',
         # https://crbug.com/274650
         'ChromeDriverTest.testCloseWindow',
         # https://code.google.com/p/chromedriver/issues/detail?id=270
@@ -771,30 +772,40 @@ class ChromeDriverAndroidTest(ChromeDriverBaseTest):
 
 class ChromeDownloadDirTest(ChromeDriverBaseTest):
 
-  def testFileDownLoad(self):
-    try:
-      self.download_dir = tempfile.mkdtemp()
-      download_name = os.path.join(self.download_dir, 'a_red_dot.png')
-      driver = self.CreateDriver(download_dir=self.download_dir)
+  def __init__(self, *args, **kwargs):
+    super(ChromeDownloadDirTest, self).__init__(*args, **kwargs)
+    self._temp_dirs = []
+
+  def CreateTempDir(self):
+    temp_dir = tempfile.mkdtemp()
+    self._temp_dirs.append(temp_dir)
+    return temp_dir
+
+  def tearDown(self):
+    # Call the superclass tearDown() method before deleting temp dirs, so that
+    # Chrome has a chance to exit before its user data dir is blown away from
+    # underneath it.
+    super(ChromeDownloadDirTest, self).tearDown()
+    for temp_dir in self._temp_dirs:
+      shutil.rmtree(temp_dir)
+
+  def testFileDownload(self):
+    download_dir = self.CreateTempDir()
+    download_name = os.path.join(download_dir, 'a_red_dot.png')
+    driver = self.CreateDriver(download_dir=download_dir)
     driver.Load(ChromeDriverTest.GetHttpUrlForFile(
         '/chromedriver/download.html'))
     driver.FindElement('id', 'red-dot').Click()
-
     deadline = time.time() + 60
     while True:
       time.sleep(0.1)
       if os.path.isfile(download_name) or time.time() > deadline:
         break
     self.assertTrue(os.path.isfile(download_name), "Failed to download file!")
-    finally:
-      shutil.rmtree(self.download_dir)
 
   def testDownloadDirectoryOverridesExistingPreferences(self):
-    """ test existing  prefence profile - check setting if it is correct  """
-
-    try:
-      user_data_dir = tempfile.mkdtemp()
-      tmp_download_dir = tempfile.mkdtemp()
+    user_data_dir = self.CreateTempDir()
+    download_dir = self.CreateTempDir()
     sub_dir = os.path.join(user_data_dir, 'Default')
     os.mkdir(sub_dir)
     prefs_file_path = os.path.join(sub_dir, 'Preferences')
@@ -811,19 +822,14 @@ class ChromeDownloadDirTest(ChromeDriverBaseTest):
 
     driver = self.CreateDriver(
         chrome_switches=['user-data-dir=' + user_data_dir],
-          download_dir = tmp_download_dir)
+        download_dir=download_dir)
 
     with open(prefs_file_path) as f:
       prefs = json.load(f)
 
-      self.assertEqual('this should not be changed', prefs['test'],
-          "Existing preference was unexpectedly overridden")
+    self.assertEqual('this should not be changed', prefs['test'])
     download = prefs['download']
-      self.assertEqual(download['default_directory'], tmp_download_dir,
-          'Download directory preference was not updated to match capabilities')
-    finally:
-      shutil.rmtree(user_data_dir)
-      shutil.rmtree(tmp_download_dir)
+    self.assertEqual(download['default_directory'], download_dir)
 
 class ChromeSwitchesCapabilityTest(ChromeDriverBaseTest):
   """Tests that chromedriver properly processes chromeOptions.args capabilities.