Update the user agent used in iOS 8.

ios/web/public/user_agent.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.
 
 #include "ios/web/public/user_agent.h"
 
 #import <UIKit/UIKit.h>
 
 #include <sys/sysctl.h>
 #include <string>
@@ skipping 15 matching lines @@
   int32 major_os_version;
   int32 minor_os_version;
   UAVersions ua_versions;
 };
 
 const UAVersions& GetUAVersionsForCurrentOS() {
   // The WebKit version can be extracted dynamically from UIWebView, but the
   // Safari version can't be, so a lookup table is used instead (for both, since
   // the reported versions should stay in sync).
   static const OSVersionMap version_map[] = {
+    { 8, 0, { "600.1.4",   "600.1.4" } },
     { 7, 1, { "9537.53",   "537.51.2" } },
     { 7, 0, { "9537.53",   "537.51.1" } },
     // 6.1 has the same values as 6.0.
     { 6, 0, { "8536.25",   "536.26" } },
   };
 
   int32 os_major_version = 0;
   int32 os_minor_version = 0;
   int32 os_bugfix_version = 0;
   base::SysInfo::OperatingSystemVersionNumbers(&os_major_version,
@@ skipping 75 matching lines @@
                       BuildOSCpuInfo().c_str(),
                       ua_versions.webkit_version_string,
                       product.c_str(),
                       kernel_version,
                       ua_versions.safari_version_string);
 
   return user_agent;
 }
 
 }  // namespace web