[ios] Fix omnibox baseWritingDirection and dismissal iOS11 bugs.

ios/chrome/browser/ui/omnibox/omnibox_popup_material_view_controller.mm

 // Copyright (c) 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "ios/chrome/browser/ui/omnibox/omnibox_popup_material_view_controller.h"
 
 #include <memory>
 
 #include "base/ios/ios_util.h"
 #include "base/mac/scoped_cftyperef.h"
@@ skipping 638 matching lines @@
   // Make a defensive copy of |match.contents|, as CopyToOmnibox() will trigger
   // a new round of autocomplete and modify |_currentResult|.
   base::string16 contents(match.contents);
   _popupView->CopyToOmnibox(contents);
 }
 
 #pragma mark -
 #pragma mark UIScrollViewDelegate
 
 - (void)scrollViewDidScroll:(UIScrollView*)scrollView {
-  // Setting the top inset of the scrollView to |kTopAndBottomPadding| causes a
-  // one time scrollViewDidScroll to |-kTopAndBottomPadding|.  It's easier to
-  // just ignore this one scroll tick.
-  if (scrollView.contentOffset.y == 0 - kTopAndBottomPadding)
-    return;
+  // TODO(crbug.com/733650): Default to the dragging check once it's been tested
+  // on trunk.
+  if (base::ios::IsRunningOnIOS11OrLater()) {
+    if (!scrollView.dragging)
+      return;
+  } else {
+    // Setting the top inset of the scrollView to |kTopAndBottomPadding| causes
+    // a one time scrollViewDidScroll to |-kTopAndBottomPadding|.  It's easier
+    // to just ignore this one scroll tick.
+    if (scrollView.contentOffset.y == 0 - kTopAndBottomPadding)
+      return;
+  }
 
   _popupView->DidScroll();
   for (OmniboxPopupMaterialRow* row in _rows) {
     row.highlighted = NO;
   }
 }
 
 // Set text alignment for popup cells.
 - (void)setTextAlignment:(NSTextAlignment)alignment {
   _alignment = alignment;
@@ skipping 112 matching lines @@
     // The delete button never disappears if you don't call this after a tap.
     // It doesn't seem to be required anywhere else.
     [_rows[indexPath.row] prepareForReuse];
     const AutocompleteMatch& match =
         ((const AutocompleteResult&)_currentResult).match_at(indexPath.row);
     _popupView->DeleteMatch(match);
   }
 }
 
 @end