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

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 d6e790bdc46580b257fb360e304530e19b0065cf..2f5c18828ee79a7e7c3c40ff6d520c13c611a5fe 100644
--- a/ios/web/navigation/history_state_operations_inttest.mm
+++ b/ios/web/navigation/history_state_operations_inttest.mm
@@ -134,21 +134,28 @@ void WaitForPageToLoad() {
     });
   }
 
-  // Loads |url| in |web_state_|.
-  void LoadUrl(const GURL& url) {
+  // Executes |block| and waits for |url| to be successfully loaded.
+  void ExecuteBlockAndWaitForLoad(const GURL& url, ProceduralBlock block) {
     ExpectPageLoad(url);
-    web::NavigationManager::WebLoadParams params(url);
-    navigation_manager()->LoadURLWithParams(params);
+    block();
     WaitForPageToLoad();
   }
 
+  // Loads |url| in |web_state_|.
+  void LoadUrl(const GURL& url) {
+    ExecuteBlockAndWaitForLoad(url, ^{
+      web::NavigationManager::WebLoadParams params(url);
+      navigation_manager()->LoadURLWithParams(params);
+    });
+  }
+
   // Reloads the page and waits for the load to finish.
   void Reload() {
-    ExpectPageLoad(current_item()->GetURL());
-    // TODO(crbug.com/677364): Use NavigationManager::Reload() once it no longer
-    // requires a web delegate.
-    web_state()->ExecuteJavaScript(ASCIIToUTF16("window.location.reload()"));
-    WaitForPageToLoad();
+    ExecuteBlockAndWaitForLoad(current_item()->GetURL(), ^{
+      // TODO(crbug.com/677364): Use NavigationManager::Reload() once it no
+      // longer requires a web delegate.
+      web_state()->ExecuteJavaScript(ASCIIToUTF16("window.location.reload()"));
+    });
   }
 
   // Set the parameters to use for state operations on the test page.
@@ -372,3 +379,47 @@ NSInteger GetIndexOfNavigationItem(const web::NavigationItem* item) {
       false, base::TimeDelta::FromSeconds(10.0));
   EXPECT_TRUE(state_object_present);
 }
+
+// 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(), current_item()->GetURL());
+  // Set up the state parameters and tap the replace state button.
+  std::string new_state("STATE OBJECT");
+  std::string empty_title("");

[Eugene But (OOO till 7-30), 2016/12/29 17:19:24]

std::string empty_title;

[kkhorimoto, 2017/01/24 05:22:54]

Done.

+  GURL empty_url("");

[Eugene But (OOO till 7-30), 2016/12/29 17:19:24]

GURL empty_url;

[kkhorimoto, 2017/01/24 05:22:54]

Done.

+  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());
+  __block bool state_object_present = false;
+  base::string16 state_object_script = ASCIIToUTF16("window.history.state");
+  base::test::ios::TimeUntilCondition(
+      ^{
+        web_state()->ExecuteJavaScript(

[Eugene But (OOO till 7-30), 2016/12/29 17:19:24]

Please use synchronous API.

[kkhorimoto, 2017/01/24 05:22:54]

Done.

+            state_object_script, base::BindBlock(^(const base::Value* result) {
+              std::string state;
+              result->GetAsString(&state);
+              state_object_present = state == new_state;
+            }));
+      },
+      ^bool {
+        return state_object_present;
+      },
+      false, base::TimeDelta::FromSeconds(10.0));
+  EXPECT_TRUE(state_object_present);

[Eugene But (OOO till 7-30), 2016/12/29 17:19:24]

No need for this line.

[kkhorimoto, 2017/01/24 05:22:54]

Done.

+}