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

ios/chrome/browser/ui/fullscreen_controller.mm

 // Copyright 2013 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/fullscreen_controller.h"
 
 #include <cmath>
 
 #include "base/logging.h"
 #include "base/mac/objc_property_releaser.h"
@@ skipping 669 matching lines @@
 - (void)triggerHeader {
   if (self.isFullScreenDisabled || ![self isScrollViewForCurrentTab])
     return;
   [self moveHeaderToRestingPosition:YES];
 }
 
 - (void)setContentViewTopContentPadding:(CGFloat)newTopPadding {
   [webViewProxy_ setTopContentPadding:newTopPadding];
 }
 
-- (void)setToolbarInsetsForHeaderOffset:(CGFloat)headerOffset
-                            forceUpdate:(BOOL)forceUpdate {
+- (void)setToolbarInsetsForHeaderOffset:(CGFloat)headerOffset {
   // Make space for the header in the scroll view.
   CGFloat topInset = self.headerHeight - headerOffset;
   UIEdgeInsets insets = self.scrollViewProxy.contentInset;
   insets.top = topInset;
 
   [self setContentViewTopContentPadding:topInset];
 }
 
 #pragma mark -
 #pragma mark CRWWebControllerObserver methods
@@ skipping 76 matching lines @@
   }
   return YES;
 }
 
 #pragma mark -
 #pragma mark CRWWebViewScrollViewProxyObserver
 
 - (void)webViewScrollViewProxyDidSetScrollView:
     (CRWWebViewScrollViewProxy*)webViewScrollViewProxy {
   webViewScrollViewProxy.contentOffset = CGPointMake(0.0, -self.headerHeight);
-  [self setToolbarInsetsForHeaderOffset:0.0 forceUpdate:YES];
+  [self setToolbarInsetsForHeaderOffset:0.0];
 }
 
 #pragma mark - UIGestureRecognizerDelegate
 
 - (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer*)gestureRecognizer {
   return YES;
 }
 
 - (BOOL)gestureRecognizer:(UIGestureRecognizer*)gestureRecognizer
     shouldRecognizeSimultaneouslyWithGestureRecognizer:
@@ skipping 21 matching lines @@
   overscrollActionsInProgress_ = NO;
 }
 
 #pragma mark - Used for testing
 
 + (void)setEnabledForTests:(BOOL)enabled {
   gEnabledForTests = enabled;
 }
 
 @end