[ios] Fix testTopSitesTileAfterRedirect on iPad.

Fixes some flake in the EG tests, and catches an error in the previous CL
crrev.com/c/1339340.  The NTP should not be created while web usage is disabled.

Bug: 905735
Change-Id: I8bd3d942c3594e4706e29ed0478a935a10602727
Reviewed-on: https://chromium-review.googlesource.com/c/1341208Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Commit-Queue: Justin Cohen <justincohen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609148}

ios/chrome/browser/ntp_tiles/ntp_tiles_egtest.mm

@@ -21,6 +21,7 @@
 #endif
 
 using chrome_test_util::ClearBrowsingDataCell;
+using chrome_test_util::ClearBrowsingDataCollectionView;
 using chrome_test_util::ClearBrowsingDataButton;
 using chrome_test_util::ConfirmClearBrowsingDataButton;
 using chrome_test_util::SettingsDoneButton;
@@ -130,6 +131,12 @@ using web::test::HttpServer;
   [ChromeEarlGreyUI tapClearBrowsingDataMenuButton:ClearBrowsingDataButton()];
   [[EarlGrey selectElementWithMatcher:ConfirmClearBrowsingDataButton()]
       performAction:grey_tap()];
+
+  // Before returning, make sure that the top of the Clear Browsing Data
+  // settings screen is visible to match the state at the start of the method.
+  [[EarlGrey selectElementWithMatcher:ClearBrowsingDataCollectionView()]
+      performAction:grey_scrollToContentEdge(kGREYContentEdgeTop)];
+
   [[EarlGrey selectElementWithMatcher:SettingsDoneButton()]
       performAction:grey_tap()];
 

ios/chrome/browser/ui/browser_view_controller.mm

@@ -1696,7 +1696,7 @@ applicationCommandEndpoint:(id<ApplicationCommands>)applicationCommandEndpoint
   self.primaryToolbarHeightConstraint.constant =
       [self primaryToolbarHeightWithInset];
 
-  if (self.currentWebState) {
+  if (self.currentWebState && self.webUsageEnabled) {
     NewTabPageTabHelper* NTPHelper =
         NewTabPageTabHelper::FromWebState(self.currentWebState);
     if (NTPHelper && NTPHelper->IsActive()) {