Use SameDocument instead of SamePage term on iOS.

ios/web/public/test/fakes/test_web_state_observer.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/public/test/fakes/test_web_state_observer.h"
 
 #include "base/memory/ptr_util.h"
 #include "ios/web/public/web_state/navigation_context.h"
 #include "ios/web/public/web_state/web_state.h"
 #include "ios/web/web_state/navigation_context_impl.h"
@@ skipping 53 matching lines @@
   navigation_item_changed_info_->web_state = web_state();
 }
 
 void TestWebStateObserver::DidFinishNavigation(NavigationContext* context) {
   did_finish_navigation_info_ =
       base::MakeUnique<web::TestDidFinishNavigationInfo>();
   did_finish_navigation_info_->web_state = web_state();
   if (context->IsSameDocument()) {
     ASSERT_FALSE(context->IsErrorPage());
     did_finish_navigation_info_->context =
-        NavigationContextImpl::CreateSamePageNavigationContext(
+        NavigationContextImpl::CreateSameDocumentNavigationContext(
             context->GetWebState(), context->GetUrl());
   } else if (context->IsErrorPage()) {
     ASSERT_FALSE(context->IsSameDocument());
     did_finish_navigation_info_->context =
         NavigationContextImpl::CreateErrorPageNavigationContext(
             context->GetWebState(), context->GetUrl());
   } else {
     did_finish_navigation_info_->context =
         NavigationContextImpl::CreateNavigationContext(context->GetWebState(),
                                                        context->GetUrl());
@@ skipping 65 matching lines @@
   start_loading_info_ = base::MakeUnique<web::TestStartLoadingInfo>();
   start_loading_info_->web_state = web_state();
 }
 
 void TestWebStateObserver::DidStopLoading() {
   stop_loading_info_ = base::MakeUnique<web::TestStopLoadingInfo>();
   stop_loading_info_->web_state = web_state();
 }
 
 }  // namespace web