[sheriff] Fix the bug that causes ClearBrowsingDataSettingsTestCase to

fail on small screens.

The refactor work on Settings makes Privacy menu larger, thus the
"Clear Browsing Data" button is hidden on iPhone 5s due to the screen
size. The EG test, ClearBrowsingDataSettingsTestCase, doesn't scroll to
find the button, so it failed.

This CL will fix the bug and stop failures on iOS12beta.

TBR=edchin@chromium.org

Bug: 907194
Change-Id: I9fc50a0979b005bcc07628c0d7ae4b3be86050bf
Reviewed-on: https://chromium-review.googlesource.com/c/1345071Reviewed-by: edchin <edchin@chromium.org>
Reviewed-by: Yi Su <mrsuyi@chromium.org>
Commit-Queue: Yi Su <mrsuyi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609950}

ios/chrome/browser/ui/settings/clear_browsing_data_egtest.mm

@@ -35,9 +35,8 @@ using chrome_test_util::SettingsMenuPrivacyButton;
 
   NSString* clearBrowsingDataDialogLabel =
       l10n_util::GetNSString(IDS_IOS_CLEAR_BROWSING_DATA_TITLE);
-  [[EarlGrey selectElementWithMatcher:ButtonWithAccessibilityLabel(
-                                          clearBrowsingDataDialogLabel)]
-      performAction:grey_tap()];
+  [ChromeEarlGreyUI tapPrivacyMenuButton:ButtonWithAccessibilityLabel(
+                                             clearBrowsingDataDialogLabel)];
 }
 
 // Test that opening the clear browsing data dialog does not cause a crash