Add a test for navigation away from error page.

This CL adds a test case to verify that navigating away from an error
page properly swaps SiteInstance when error page isolation is enabled.

Bug: 838161
Change-Id: Ibe16bf39b24dd1d18666c4383bfba5777f8c965e
Reviewed-on: https://chromium-review.googlesource.com/1122840Reviewed-by: Alex Moshchuk <alexmos@chromium.org>
Commit-Queue: Nasko Oskov <nasko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#571935}

content/browser/frame_host/render_frame_host_manager_browsertest.cc

@@ -4388,6 +4388,76 @@ IN_PROC_BROWSER_TEST_F(RenderFrameHostManagerTest, ErrorPageNavigationReload) {
           shell()->web_contents()->GetSiteInstance()->GetProcess()->GetID()));
 }
 
+// Test to verify that navigating away from an error page results in correct
+// change in SiteInstance.
+IN_PROC_BROWSER_TEST_F(RenderFrameHostManagerTest,
+                       ErrorPageNavigationAfterError) {
+  // This test is only valid if error page isolation is enabled.
+  if (!SiteIsolationPolicy::IsErrorPageIsolationEnabled(true))
+    return;
+
+  StartEmbeddedServer();
+  GURL url(embedded_test_server()->GetURL("/title1.html"));
+  GURL error_url(embedded_test_server()->GetURL("/empty.html"));
+  std::unique_ptr<URLLoaderInterceptor> url_interceptor =
+      SetupRequestFailForURL(error_url);
+  NavigationControllerImpl& nav_controller =
+      static_cast<NavigationControllerImpl&>(
+          shell()->web_contents()->GetController());
+
+  // Start with a successful navigation to a document.
+  EXPECT_TRUE(NavigateToURL(shell(), url));
+  scoped_refptr<SiteInstance> success_site_instance =
+      shell()->web_contents()->GetMainFrame()->GetSiteInstance();
+  EXPECT_EQ(1, nav_controller.GetEntryCount());
+
+  // Navigate to an url resulting in an error page.
+  EXPECT_FALSE(NavigateToURL(shell(), error_url));
+  EXPECT_EQ(
+      GURL(kUnreachableWebDataURL),
+      shell()->web_contents()->GetMainFrame()->GetSiteInstance()->GetSiteURL());
+  EXPECT_EQ(
+      GURL(kUnreachableWebDataURL),
+      ChildProcessSecurityPolicyImpl::GetInstance()->GetOriginLock(
+          shell()->web_contents()->GetSiteInstance()->GetProcess()->GetID()));
+  EXPECT_EQ(2, nav_controller.GetEntryCount());
+
+  // Navigate again to the initial successful document, expecting a new
+  // navigation and new SiteInstance.
+  EXPECT_TRUE(NavigateToURL(shell(), url));
+  EXPECT_NE(
+      GURL(kUnreachableWebDataURL),
+      shell()->web_contents()->GetMainFrame()->GetSiteInstance()->GetSiteURL());
+  EXPECT_EQ(
+      success_site_instance->GetSiteURL(),
+      shell()->web_contents()->GetMainFrame()->GetSiteInstance()->GetSiteURL());
+  EXPECT_NE(success_site_instance,
+            shell()->web_contents()->GetMainFrame()->GetSiteInstance());
+  EXPECT_EQ(3, nav_controller.GetEntryCount());
+
+  // Repeat again using a renderer-initiated navigation for the successful one.
+  EXPECT_FALSE(NavigateToURL(shell(), error_url));
+  EXPECT_EQ(
+      GURL(kUnreachableWebDataURL),
+      shell()->web_contents()->GetMainFrame()->GetSiteInstance()->GetSiteURL());
+  EXPECT_EQ(
+      GURL(kUnreachableWebDataURL),
+      ChildProcessSecurityPolicyImpl::GetInstance()->GetOriginLock(
+          shell()->web_contents()->GetSiteInstance()->GetProcess()->GetID()));
+  EXPECT_EQ(4, nav_controller.GetEntryCount());
+  {
+    TestNavigationObserver observer(shell()->web_contents());
+    EXPECT_TRUE(
+        ExecuteScript(shell(), "location.href = '" + url.spec() + "';"));
+    observer.Wait();
+    EXPECT_TRUE(observer.last_navigation_succeeded());
+  }
+  EXPECT_EQ(5, nav_controller.GetEntryCount());
+  EXPECT_NE(
+      GURL(kUnreachableWebDataURL),
+      shell()->web_contents()->GetMainFrame()->GetSiteInstance()->GetSiteURL());
+}
+
 // A NavigationThrottle implementation that blocks all outgoing navigation
 // requests for a specific WebContents. It is used to block navigations to
 // WebUI URLs in the following test.