Created test for restoring state object after back/forward navigation.

ios/web/navigation/history_state_operations_inttest.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.
 
 #include "base/memory/ptr_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/test/ios/wait_util.h"
 #import "ios/web/navigation/navigation_item_impl.h"
@@ skipping 290 matching lines @@
   GURL empty_url;
   SetStateParams(new_state, empty_title, empty_url);
   ASSERT_TRUE(web::test::TapWebViewElementWithId(web_state(), kReplaceStateId));
   // Reload the page and check that the state object is present.
   Reload();
   ASSERT_TRUE(IsOnLoadTextVisible());
   base::test::ios::WaitUntilCondition(^bool {
     return GetJavaScriptState() == new_state;
   });
 }
+
+// Tests that the state object is correctly set for a page after a back/forward
+// navigation.
+TEST_F(HistoryStateOperationsTest, StateReplacementBackForward) {
+  // Navigate to about:blank then navigate back to the test page.  The created
+  // NavigationItem can be used later to verify that the state is replaced
+  // rather than pushed.
+  GURL about_blank("about:blank");
+  LoadUrl(about_blank);
+  ExecuteBlockAndWaitForLoad(state_operations_url(), ^{
+    navigation_manager()->GoBack();
+  });
+  ASSERT_EQ(state_operations_url(), GetLastCommittedItem()->GetURL());
+  // Set up the state parameters and tap the replace state button.
+  std::string new_state("STATE OBJECT");
+  std::string empty_title("");
+  GURL empty_url("");
+  SetStateParams(new_state, empty_title, empty_url);
+  ASSERT_TRUE(web::test::TapWebViewElementWithId(web_state(), kReplaceStateId));
+  // Go forward and back, then check that the state object is present.
+  ExecuteBlockAndWaitForLoad(about_blank, ^{
+    navigation_manager()->GoForward();
+  });
+  ExecuteBlockAndWaitForLoad(state_operations_url(), ^{
+    navigation_manager()->GoBack();
+  });
+  ASSERT_TRUE(IsOnLoadTextVisible());
+  base::test::ios::WaitUntilCondition(^bool {
+    return GetJavaScriptState() == new_state;
+  });
+}