[ios] Fix Constraints between Recent Tabs and Parent View in TabGrid

Bug: 867717
Change-Id: I85bd1f1c0404e536236a6b08787da499a5d7da41
Reviewed-on: https://chromium-review.googlesource.com/1152107Reviewed-by: edchin <edchin@chromium.org>
Commit-Queue: Chris Lu <thegreenfrog@chromium.org>
Cr-Commit-Position: refs/heads/master@{#578449}

ios/chrome/browser/ui/tab_grid/tab_grid_view_controller.mm

@@ -575,7 +575,7 @@ NSUInteger GetPageIndexFromPage(TabGridPage page) {
     [viewController.view.bottomAnchor
         constraintEqualToAnchor:parentView.bottomAnchor],
     [viewController.view.leadingAnchor
-        constraintEqualToAnchor:parentView.trailingAnchor],
+        constraintEqualToAnchor:parentView.leadingAnchor],
     [viewController.view.trailingAnchor
         constraintEqualToAnchor:parentView.trailingAnchor],
   ];