[ios] Fix ipad infobar snapshot

Pre-bijou, infobars were on displayed on top of the web content below
the omnibox. Today, infobars are on the bottom, having no difference
with the phone form-factor.

This CL removes special casing code for snapshotting in iPad. This
should have been removed when bijou was launched.

Bug: 918759
Change-Id: Ic18524ac47606b2d1b6ee1c254220465d64a8d71
Reviewed-on: https://chromium-review.googlesource.com/c/1394423Reviewed-by: edchin <edchin@chromium.org>
Reviewed-by: Justin Cohen <justincohen@chromium.org>
Reviewed-by: Sergio Collazos <sczs@chromium.org>
Commit-Queue: edchin <edchin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#619655}

ios/chrome/browser/ui/browser_view_controller.mm

@@ -2991,12 +2991,6 @@ NSString* const kBrowserViewControllerSnackbarCategory =
 // Provides a view that encompasses currently displayed infobar(s) or nil
 // if no infobar is presented.
 - (UIView*)infoBarOverlayViewForTab:(Tab*)tab {
-  if (IsIPadIdiom()) {
-    // Not using overlays on iPad because the content is pushed down by
-    // infobar and the transition between snapshot and fresh page can
-    // cause both snapshot and real infobars to appear at the same time.
-    return nil;
-  }
   if (tab && self.tabModel.currentTab == tab) {
     DCHECK(self.currentWebState);
     DCHECK(self.infobarContainerCoordinator);
@@ -3015,9 +3009,6 @@ NSString* const kBrowserViewControllerSnackbarCategory =
     // no _infobarContainerCoordinator instantiated yet.
     // Return offset outside of tab.
     return CGRectGetMaxY(self.view.frame);
-  } else if (IsIPadIdiom()) {
-    // The infobars on iPad are display at the top of a tab.
-    return CGRectGetMinY([self visibleFrameForTab:self.tabModel.currentTab]);
   } else {
     // The infobars on iPhone are displayed at the bottom of a tab.
     CGRect visibleFrame = [self visibleFrameForTab:self.tabModel.currentTab];