[ios] Removed RequestTracker dependency from WebLoadParams.

ios/web/navigation/web_load_params.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.
 
 #include "ios/web/navigation/web_load_params.h"
 
 namespace web {
 
 WebLoadParams::WebLoadParams(const GURL& url)
     : url(url),
       transition_type(ui::PAGE_TRANSITION_LINK),
       is_renderer_initiated(false),
-      cache_mode(net::RequestTracker::CACHE_NORMAL),
       post_data(NULL) {
 }
 
 WebLoadParams::~WebLoadParams() {}
 
 WebLoadParams::WebLoadParams(const WebLoadParams& other)
     : url(other.url),
       referrer(other.referrer),
       transition_type(other.transition_type),
       is_renderer_initiated(other.is_renderer_initiated),
-      cache_mode(other.cache_mode),
       extra_headers([other.extra_headers copy]),
       post_data([other.post_data copy]) {
 }
 
 WebLoadParams& WebLoadParams::operator=(
     const WebLoadParams& other) {
   url = other.url;
   referrer = other.referrer;
   is_renderer_initiated = other.is_renderer_initiated;
   transition_type = other.transition_type;
-  cache_mode = other.cache_mode;
   extra_headers.reset([other.extra_headers copy]);
   post_data.reset([other.post_data copy]);
 
   return *this;
 }
 
 }  // namespace web