Use SameDocument instead of SamePage term on iOS.

ios/web/web_state/navigation_context_impl.mm

 // Copyright 2017 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/web_state/navigation_context_impl.h"
 
 #include "base/memory/ptr_util.h"
 
 namespace web {
 
 // static
 std::unique_ptr<NavigationContext>
 NavigationContextImpl::CreateNavigationContext(WebState* web_state,
                                                const GURL& url) {
   std::unique_ptr<NavigationContext> resut(new NavigationContextImpl(
       web_state, url, false /* is_same_document */, false /* is_error_page */));
   return resut;
 }
 
 // static
 std::unique_ptr<NavigationContext>
-NavigationContextImpl::CreateSamePageNavigationContext(WebState* web_state,
-                                                       const GURL& url) {
+NavigationContextImpl::CreateSameDocumentNavigationContext(WebState* web_state,
+                                                           const GURL& url) {
   std::unique_ptr<NavigationContext> result(new NavigationContextImpl(
       web_state, url, true /* is_same_document */, false /* is_error_page */));
   return result;
 }
 
 // static
 std::unique_ptr<NavigationContext>
 NavigationContextImpl::CreateErrorPageNavigationContext(WebState* web_state,
                                                         const GURL& url) {
   std::unique_ptr<NavigationContext> result(new NavigationContextImpl(
@@ skipping 22 matching lines @@
                                              bool is_same_document,
                                              bool is_error_page)
     : web_state_(web_state),
       url_(url),
       is_same_document_(is_same_document),
       is_error_page_(is_error_page) {}
 
 NavigationContextImpl::~NavigationContextImpl() = default;
 
 }  // namespace web