Moved NavigationManagerImpl serialization out of CRWSessionController.

ios/web/navigation/navigation_manager_impl.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/web/navigation/navigation_manager_impl.h"
 
 #include <stddef.h>
 
 #include <utility>
 
@@ skipping 52 matching lines @@
   url = other.url;
   referrer = other.referrer;
   is_renderer_initiated = other.is_renderer_initiated;
   transition_type = other.transition_type;
   extra_headers.reset([other.extra_headers copy]);
   post_data.reset([other.post_data copy]);
 
   return *this;
 }
 
-NavigationManagerImpl::NavigationManagerImpl(
-    NavigationManagerDelegate* delegate,
-    BrowserState* browser_state)
-    : delegate_(delegate),
-      browser_state_(browser_state),
-      facade_delegate_(nullptr) {
-  DCHECK(browser_state_);
-}
+NavigationManagerImpl::NavigationManagerImpl()
+    : delegate_(nullptr), browser_state_(nullptr), facade_delegate_(nullptr) {}
 
 NavigationManagerImpl::~NavigationManagerImpl() {
   // The facade layer should be deleted before this object.
   DCHECK(!facade_delegate_);
 
   [session_controller_ setNavigationManager:nullptr];
 }
 
+void NavigationManagerImpl::SetDelegate(NavigationManagerDelegate* delegate) {
+  delegate_ = delegate;
+}
+
+void NavigationManagerImpl::SetBrowserState(BrowserState* browser_state) {
+  browser_state_ = browser_state;
+}
+
 void NavigationManagerImpl::SetSessionController(
     CRWSessionController* session_controller) {
   session_controller_.reset(session_controller);
   [session_controller_ setNavigationManager:this];
 }
 
 void NavigationManagerImpl::InitializeSession(NSString* window_name,
                                               NSString* opener_id,
                                               BOOL opened_by_dom,
                                               int opener_navigation_index) {
@@ skipping 298 matching lines @@
 }
 
 bool NavigationManagerImpl::IsRedirectItemAtIndex(int index) const {
   DCHECK_GT(index, 0);
   DCHECK_LT(index, GetItemCount());
   ui::PageTransition transition = GetItemAtIndex(index)->GetTransitionType();
   return transition & ui::PAGE_TRANSITION_IS_REDIRECT_MASK;
 }
 
 }  // namespace web