Revert 'Bypass UIWebView.scrollView's contentInset implementation with UIScrollView's.

ios/chrome/browser/ui/overscroll_actions/overscroll_actions_controller.mm

 // Copyright 2015 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/overscroll_actions/overscroll_actions_controller.h"
 
 #import <QuartzCore/QuartzCore.h>
 
 #include <algorithm>
 #include "base/logging.h"
@@ skipping 569 matching lines @@
   } else {
     return static_cast<id<OverscrollActionsScrollView>>(
         _webViewScrollViewProxy.get());
   }
 }
 
 - (void)setScrollViewContentInset:(UIEdgeInsets)contentInset {
   if (_scrollview)
     [_scrollview setContentInset:contentInset];
   else
-    [_webViewScrollViewProxy setContentInsetFast:contentInset];
+    [_webViewScrollViewProxy setContentInset:contentInset];
 }
 
 - (UIView<RelaxedBoundsConstraintsHitTestSupport>*)headerView {
   return [self.delegate headerView];
 }
 
 - (void)incrementOverscrollActionLockForNotification:(NSNotification*)notif {
   if (![_lockIncrementNotifications containsObject:notif.name]) {
     [_lockIncrementNotifications addObject:notif.name];
     ++_overscrollActionLock;
@@ skipping 271 matching lines @@
   _panGestureRecognizer.enabled = YES;
   [self scrollView].panGestureRecognizer.enabled = NO;
   [self scrollView].panGestureRecognizer.enabled = YES;
   [self startBounceWithInitialVelocity:CGPointZero];
   [self.delegate
       overscrollActionsController:self
                  didTriggerAction:self.overscrollActionView.selectedAction];
 }
 
 @end