Fix the T-Rex easter egg on iOS.

ios/web/web_state/web_view_internal_creation_util.mm

 // Copyright 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/web/web_state/web_view_internal_creation_util.h"
 
 #include "base/logging.h"
 #include "base/strings/sys_string_conversions.h"
 #include "ios/web/public/web_client.h"
 #import "ios/web/web_state/ui/wk_web_view_configuration_provider.h"
@@ skipping 15 matching lines @@
   DCHECK_EQ([config_provider.GetWebViewConfiguration() processPool],
             [configuration processPool]);
 }
 
 }  // namespace
 
 WKWebView* CreateWKWebView(CGRect frame,
                            WKWebViewConfiguration* configuration,
                            BrowserState* browser_state,
                            BOOL use_desktop_user_agent) {
-  WKWebView* web_view = CreateWKWebView(frame, configuration, browser_state);
-  web_view.customUserAgent = base::SysUTF8ToNSString(
-      web::GetWebClient()->GetUserAgent(use_desktop_user_agent));
+  VerifyWKWebViewCreationPreConditions(browser_state, configuration);
+
+  GetWebClient()->PreWebViewCreation();
+  WKWebView* web_view =
+      [[WKWebView alloc] initWithFrame:frame configuration:configuration];
+
+  // By default the web view uses a very sluggish scroll speed. Set it to a more
+  // reasonable value.
+  web_view.scrollView.decelerationRate = UIScrollViewDecelerationRateNormal;
+
+  // Starting in iOS10, |allowsLinkPreview| defaults to YES.  This should be
+  // disabled since the default implementation will open the link in Safari.
+  // TODO(crbug.com/622746): Remove once web// link preview implementation is
+  // created.
+  web_view.allowsLinkPreview = NO;
+
   return web_view;
 }
 
 WKWebView* CreateWKWebView(CGRect frame,
                            WKWebViewConfiguration* configuration,
                            BrowserState* browser_state) {
-  VerifyWKWebViewCreationPreConditions(browser_state, configuration);
-
-  GetWebClient()->PreWebViewCreation();
-  WKWebView* result =
-      [[WKWebView alloc] initWithFrame:frame configuration:configuration];
-
-  // By default the web view uses a very sluggish scroll speed. Set it to a more
-  // reasonable value.
-  result.scrollView.decelerationRate = UIScrollViewDecelerationRateNormal;
-
-  // Starting in iOS10, |allowsLinkPreview| defaults to YES.  This should be
-  // disabled since the default implementation will open the link in Safari.
-  // TODO(crbug.com/622746): Remove once web// link preview implementation is
-  // created.
-  result.allowsLinkPreview = NO;
-
-  return result;
+  BOOL use_desktop_user_agent = NO;
+  return CreateWKWebView(frame, configuration, browser_state,
+                         use_desktop_user_agent);
 }
 
 }  // namespace web