Created test verifying setting the state object via replaceState()

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"
 #import "ios/web/public/navigation_item.h"
 #import "ios/web/public/navigation_manager.h"
 #import "ios/web/public/test/http_server.h"
 #include "ios/web/public/test/http_server_util.h"
 #import "ios/web/public/test/web_view_interaction_test_util.h"
 #import "ios/web/public/web_state/web_state.h"
 #import "ios/web/test/web_int_test.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/gtest_mac.h"
 #include "url/url_canon.h"
@@ skipping 56 matching lines @@
                       const std::string& title,
                       const GURL& url) {
     ASSERT_EQ(state_operations_url(), GetLastCommittedItem()->GetURL());
     std::string url_spec = url.possibly_invalid_spec();
     NSString* set_params_script = [NSString
         stringWithFormat:kUpdateStateParamsScriptFormat, state_object.c_str(),
                          title.c_str(), url_spec.c_str()];
     ExecuteJavaScript(set_params_script);
   }
 
+  // Returns the state object returned by JavaScript.
+  std::string GetJavaScriptState() {
+    return base::SysNSStringToUTF8(ExecuteJavaScript(@"window.history.state"));
+  }
+
   // Executes JavaScript to check whether the onload text is visible.
   bool IsOnLoadTextVisible() {
     return [ExecuteJavaScript(kOnLoadCheckScript) boolValue];
   }
 
   // Executes JavaScript to check whether the no-op text is visible.
   bool IsNoOpTextVisible() {
     return [ExecuteJavaScript(kNoOpCheckScript) boolValue];
   }
 
@@ skipping 136 matching lines @@
   SetStateParams(empty_state, new_title, empty_url);
   ASSERT_TRUE(web::test::TapWebViewElementWithId(web_state(), kReplaceStateId));
   // Wait for the title to be reflected in the NavigationItem.
   base::test::ios::WaitUntilCondition(^bool {
     return GetLastCommittedItem()->GetTitle() == ASCIIToUTF16(new_title);
   });
   // Verify that the forward navigation was not pruned.
   EXPECT_EQ(GetIndexOfNavigationItem(GetLastCommittedItem()) + 1,
             GetIndexOfNavigationItem(about_blank_item));
 }
+
+// Tests that calling window.history.replaceState() with a new state object
+// replaces the state object for the current NavigationItem.
+TEST_F(HistoryStateOperationsTest, StateReplacement) {
+  // 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);
+  web::NavigationItem* about_blank_item = GetLastCommittedItem();
+  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));
+  // Verify that the state is reflected in the JavaScript context.
+  base::test::ios::WaitUntilCondition(^bool {
+    return GetJavaScriptState() == new_state;
+  });
+  // Verify that the state is reflected in the latest NavigationItem.
+  std::string serialized_state("\"STATE OBJECT\"");
+  base::test::ios::WaitUntilCondition(^bool {
+    web::NavigationItemImpl* item =
+        static_cast<web::NavigationItemImpl*>(GetLastCommittedItem());
+    std::string item_state =
+        base::SysNSStringToUTF8(item->GetSerializedStateObject());
+    return item_state == serialized_state;
+  });
+  // Verify that the forward navigation was not pruned.
+  EXPECT_EQ(GetIndexOfNavigationItem(GetLastCommittedItem()) + 1,
+            GetIndexOfNavigationItem(about_blank_item));
+}