Use SameDocument instead of SamePage term on iOS.

ios/web/web_state/navigation_context_impl_unittest.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"
 
 #import "ios/web/public/test/fakes/test_web_state.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/platform_test.h"
 
@@ skipping 13 matching lines @@
   std::unique_ptr<NavigationContext> context =
       NavigationContextImpl::CreateNavigationContext(&web_state_, url_);
   ASSERT_TRUE(context);
 
   EXPECT_EQ(&web_state_, context->GetWebState());
   EXPECT_EQ(url_, context->GetUrl());
   EXPECT_FALSE(context->IsSameDocument());
   EXPECT_FALSE(context->IsErrorPage());
 }
 
-// Tests CreateSamePageNavigationContext factory method.
-TEST_F(NavigationContextImplTest, SamePageNavigationContext) {
+// Tests CreateSameDocumentNavigationContext factory method.
+TEST_F(NavigationContextImplTest, SameDocumentNavigationContext) {
   std::unique_ptr<NavigationContext> context =
-      NavigationContextImpl::CreateSamePageNavigationContext(&web_state_, url_);
+      NavigationContextImpl::CreateSameDocumentNavigationContext(&web_state_,
+                                                                 url_);
   ASSERT_TRUE(context);
 
   EXPECT_EQ(&web_state_, context->GetWebState());
   EXPECT_EQ(url_, context->GetUrl());
   EXPECT_TRUE(context->IsSameDocument());
   EXPECT_FALSE(context->IsErrorPage());
 }
 
 // Tests CreateErrorPageNavigationContext factory method.
 TEST_F(NavigationContextImplTest, ErrorPageNavigationContext) {
   std::unique_ptr<NavigationContext> context =
       NavigationContextImpl::CreateErrorPageNavigationContext(&web_state_,
                                                               url_);
   ASSERT_TRUE(context);
 
   EXPECT_EQ(&web_state_, context->GetWebState());
   EXPECT_EQ(url_, context->GetUrl());
   EXPECT_FALSE(context->IsSameDocument());
   EXPECT_TRUE(context->IsErrorPage());
 }
 
 }  // namespace web