Use SameDocument instead of SamePage term on iOS.

ios/web/public/test/fakes/crw_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.
 
 #import "ios/web/public/test/fakes/crw_test_web_state_observer.h"
 
 #include "base/memory/ptr_util.h"
 #include "ios/web/public/web_state/navigation_context.h"
 #include "ios/web/web_state/navigation_context_impl.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ skipping 131 matching lines @@
 }
 
 - (void)webState:(web::WebState*)webState
     didFinishNavigation:(web::NavigationContext*)navigation {
   _didFinishNavigationInfo =
       base::MakeUnique<web::TestDidFinishNavigationInfo>();
   _didFinishNavigationInfo->web_state = webState;
   if (navigation->IsSameDocument()) {
     ASSERT_FALSE(navigation->IsErrorPage());
     _didFinishNavigationInfo->context =
-        web::NavigationContextImpl::CreateSamePageNavigationContext(
+        web::NavigationContextImpl::CreateSameDocumentNavigationContext(
             navigation->GetWebState(), navigation->GetUrl());
   } else if (navigation->IsErrorPage()) {
     ASSERT_FALSE(navigation->IsSameDocument());
     _didFinishNavigationInfo->context =
         web::NavigationContextImpl::CreateErrorPageNavigationContext(
             navigation->GetWebState(), navigation->GetUrl());
   } else {
     _didFinishNavigationInfo->context =
         web::NavigationContextImpl::CreateNavigationContext(
             navigation->GetWebState(), navigation->GetUrl());
@@ skipping 83 matching lines @@
   _stopLoadingInfo = base::MakeUnique<web::TestStopLoadingInfo>();
   _stopLoadingInfo->web_state = webState;
 }
 
 - (void)webStateDidStartLoading:(web::WebState*)webState {
   _startLoadingInfo = base::MakeUnique<web::TestStartLoadingInfo>();
   _startLoadingInfo->web_state = webState;
 }
 
 @end