Created test for title replacement via window.history.replaceState().

ios/web/navigation/history_state_operations_inttest.mm

Index: ios/web/navigation/history_state_operations_inttest.mm
diff --git a/ios/web/navigation/history_state_operations_inttest.mm b/ios/web/navigation/history_state_operations_inttest.mm
index 88feaf519e6203a7164943397bfa7a840e077303..52cc4f2a149fd0cced972562b09fc14a0ba1fe08 100644
--- a/ios/web/navigation/history_state_operations_inttest.mm
+++ b/ios/web/navigation/history_state_operations_inttest.mm
@@ -262,3 +262,36 @@ NSInteger GetIndexOfNavigationItem(const web::NavigationItem* item) {
   ASSERT_TRUE(web::test::TapWebViewElementWithId(web_state(), kReplaceStateID));
   EXPECT_TRUE(LastOperationWasNoOp());
 }
+
+// Tests that calling window.history.replaceState() with only a new title
+// successfully replaces the current NavigationItem's title.
+// TODO(crbug.com/677356): Enable this test once the NavigationItem's title is
+// updated from within the web layer.
+TEST_F(HistoryStateOperationsTest, DISABLED_TitleReplacement) {
+  // Navigate to about:blank then navigate back to the test page.  The created
+  // NavigationItem can be used later to verify that the title is replaced
+  // rather than pushed.
+  GURL about_blank("about:blank");
+  LoadUrl(about_blank);
+  web::NavigationItem* about_blank_item = current_item();
+  ExpectPageLoad(state_operations_url());
+  navigation_manager()->GoBack();
+  WaitForPageToLoad();
+  ASSERT_EQ(state_operations_url(), current_item()->GetURL());
+  // Set up the state parameters and tap the replace state button.
+  std::string empty_state("");

[Eugene But (OOO till 7-30), 2016/12/29 17:09:48]

std::string empty_state;

[kkhorimoto, 2017/01/24 04:40:58]

Done.

+  std::string new_title("NEW TITLE");
+  GURL empty_url("");

[Eugene But (OOO till 7-30), 2016/12/29 17:09:48]

GURL empty_url;

[kkhorimoto, 2017/01/24 04:40:58]

Done.

+  SetStateParams(empty_state, new_title, empty_url);
+  ASSERT_TRUE(web::test::TapWebViewElementWithId(web_state(), kReplaceStateID));
+  // Verify that the title is reflected in the latest NavigationItem.
+  __block bool title_updated = false;
+  base::test::ios::WaitUntilCondition(^bool {
+    title_updated = current_item()->GetTitle() == ASCIIToUTF16(new_title);

[Eugene But (OOO till 7-30), 2016/12/29 17:09:48]

nit: |return current_item()->GetTitle() == ASCIIToUTF16(new_title);|

[kkhorimoto, 2017/01/24 04:40:58]

Done.

+    return title_updated;
+  });
+  EXPECT_TRUE(title_updated);

[Eugene But (OOO till 7-30), 2016/12/29 17:09:48]

You don't need this. WaitUntilCondition will not successfully return until
|title_updated| is true.

[kkhorimoto, 2017/01/24 04:40:58]

Done.

+  // Verify that the forward navigation was not pruned.
+  EXPECT_EQ(GetIndexOfNavigationItem(current_item()) + 1,
+            GetIndexOfNavigationItem(about_blank_item));
+}