Fixed title updating for back forward navigation.

ios/web/web_state/ui/crw_wk_navigation_states_unittest.mm

 // Copyright 2016 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/web_state/ui/crw_wk_navigation_states.h"
 
 #import <WebKit/WebKit.h>
 
 #import "base/mac/scoped_nsobject.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ skipping 13 matching lines @@
   base::scoped_nsobject<WKNavigation> navigation1_;
   base::scoped_nsobject<WKNavigation> navigation2_;
   base::scoped_nsobject<CRWWKNavigationStates> states_;
 };
 
 // Tests |lastAddedNavigation| method.
 TEST_F(CRWWKNavigationStatesTest, LastAddedNavigation) {
   // navigation_1 is the only navigation and it is the latest.
   [states_ setState:WKNavigationState::REQUESTED forNavigation:navigation1_];
   EXPECT_EQ(navigation1_, [states_ lastAddedNavigation]);
+  EXPECT_EQ(WKNavigationState::REQUESTED, [states_ lastAddedNavigationState]);
 
   // navigation_2 is added later and hence the latest.
   [states_ setState:WKNavigationState::REQUESTED forNavigation:navigation2_];
   EXPECT_EQ(navigation2_, [states_ lastAddedNavigation]);
+  EXPECT_EQ(WKNavigationState::REQUESTED, [states_ lastAddedNavigationState]);
 
   // Updating state for existing navigation does not make it the latest.
   [states_ setState:WKNavigationState::STARTED forNavigation:navigation1_];
   EXPECT_EQ(navigation2_, [states_ lastAddedNavigation]);
+  EXPECT_EQ(WKNavigationState::REQUESTED, [states_ lastAddedNavigationState]);
+
+  // navigation_2 is still the latest.
+  [states_ setState:WKNavigationState::STARTED forNavigation:navigation2_];
+  EXPECT_EQ(navigation2_, [states_ lastAddedNavigation]);
+  EXPECT_EQ(WKNavigationState::STARTED, [states_ lastAddedNavigationState]);
 }
 
 }  // namespace web