[ChromeDriver] Fix testChromeDriverSendLargeData on Android

testChromeDriverSendLargeData used to use string concatenation to
generate a long string, which was slow and can timeout on slow devices.
Improving efficiency by using String.repeat() instead, to make it fast
enough for Android.

Bug: chromedriver:1175
Change-Id: I9b030a43c82cdbe69c374718a307a66f57cf04a3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1763171Reviewed-by: Rohan Pavone <rohpavone@chromium.org>
Commit-Queue: John Chen <johnchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#689063}

chrome/test/chromedriver/test/run_py_tests.py

@@ -197,8 +197,6 @@ _ANDROID_NEGATIVE_FILTER['chrome'] = (
         'SessionHandlingTest.testGetSessions',
         # Android doesn't use the chrome://print dialog.
         'ChromeDriverTest.testCanSwitchToPrintPreviewDialog',
-        # https://bugs.chromium.org/p/chromedriver/issues/detail?id=1175
-        'ChromeDriverTest.testChromeDriverSendLargeData',
         # Chrome 44+ for Android doesn't dispatch the dblclick event
         'ChromeDriverTest.testMouseDoubleClick',
         # Page cannot be loaded from file:// URI in Android unless it
@@ -1382,7 +1380,7 @@ class ChromeDriverTest(ChromeDriverBaseTestWithWebServer):
     self._driver.ExecuteScript('debugger;')
 
   def testChromeDriverSendLargeData(self):
-    script = 'var s = ""; for (var i = 0; i < 10e6; i++) s += "0"; return s;'
+    script = 'return "0".repeat(10e6);'
     lots_of_data = self._driver.ExecuteScript(script)
     self.assertEquals('0'.zfill(int(10e6)), lots_of_data)