[ChromeDriver] Delete flaky testHasFocusOnStartup

Delete test case ChromeDriverTest.testHasFocusOnStartup, which is
inherently flaky, as any pop-up window can cause Chrome to lose focus.

Bug: 868376
Change-Id: Ie9b737791df3eadb85fb9525775963c9a997be7b
Reviewed-on: https://chromium-review.googlesource.com/1157072Reviewed-by: Caleb Rouleau <crouleau@chromium.org>
Commit-Queue: John Chen <johnchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#579532}

chrome/test/chromedriver/test/run_py_tests.py

@@ -113,8 +113,6 @@ _OS_SPECIFIC_FILTER['mac'] = [
     'ChromeDriverTest.testWindowMinimize',
     # https://bugs.chromium.org/p/chromedriver/issues/detail?id=2522
     'ChromeDriverTest.testWindowMaximize',
-    # https://bugs.chromium.org/p/chromium/issues/detail?id=868376
-    'ChromeDriverTest.testHasFocusOnStartup',
 ]
 
 _DESKTOP_NEGATIVE_FILTER = [
@@ -1098,11 +1096,6 @@ class ChromeDriverTest(ChromeDriverBaseTestWithWebServer):
     self._driver.MouseClick(2)
     self.assertTrue(self._driver.ExecuteScript('return success'))
 
-  def testHasFocusOnStartup(self):
-    # Some pages (about:blank) cause Chrome to put the focus in URL bar.
-    # This breaks tests depending on focus.
-    self.assertTrue(self._driver.ExecuteScript('return document.hasFocus()'))
-
   def testTabCrash(self):
     # If a tab is crashed, the session will be deleted.
     # When 31 is released, will reload the tab instead.