Fix initial erroneous navigation in iframe to not add history entry.

chrome/browser/errorpage_browsertest.cc

Index: chrome/browser/errorpage_browsertest.cc
diff --git a/chrome/browser/errorpage_browsertest.cc b/chrome/browser/errorpage_browsertest.cc
index d87b5ac9137af10d024fcc58ee9ebad7cfa55d02..a1ecd1471231b6912c173d0fe64184d97aac11c7 100644
--- a/chrome/browser/errorpage_browsertest.cc
+++ b/chrome/browser/errorpage_browsertest.cc
@@ -11,6 +11,7 @@
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/test/base/in_process_browser_test.h"
 #include "chrome/test/base/ui_test_utils.h"
+#include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/test/browser_test_utils.h"
 #include "content/public/test/test_navigation_observer.h"
@@ -210,6 +211,11 @@ IN_PROC_BROWSER_TEST_F(ErrorPageTest, IFrameDNSError_Basic) {
           base::FilePath(FILE_PATH_LITERAL("iframe_dns_error.html"))),
       "Blah",
       1);
+  // We expect to have two history entries, since we started off with navigation
+  // to "about:blank" and then navigated to "iframe_dns_error.html".
+  EXPECT_EQ(2,
+      browser()->tab_strip_model()->GetActiveWebContents()->
+          GetController().GetEntryCount());
 }
 
 // This test fails regularly on win_rel trybots. See crbug.com/121540
@@ -241,6 +247,39 @@ IN_PROC_BROWSER_TEST_F(ErrorPageTest, MAYBE_IFrameDNSError_GoBackAndForward) {
   GoForwardAndWaitForTitle("Blah", 1);
 }
 
+// Test that a DNS error occuring in an iframe, once the main document is
+// completed loading, does not result in an additional session history entry.
+// To ensure that the main document has completed loading, JavaScript is used to
+// inject an iframe after loading is done.
+IN_PROC_BROWSER_TEST_F(ErrorPageTest, IFrameDNSError_JavaScript) {
+  content::WebContents* wc =
+      browser()->tab_strip_model()->GetActiveWebContents();
+  GURL fail_url =
+      URLRequestFailedJob::GetMockHttpUrl(net::ERR_NAME_NOT_RESOLVED);
+  std::string script = "var frame = document.createElement('iframe');"
+                       "frame.src = '" + fail_url.spec() + "';"
+                       "document.body.appendChild(frame);"
+                       "document.title = 'done';";

[mmenke, 2013/05/22 17:25:50]

This failed consistently prior to the fix?  My concern here is that the history
could theoretically be updated only after the frame commits, which happens
asynchronously.

Is there some way we could wait until after the iframe has been filled with the
error page?

[nasko, 2013/05/22 17:52:53]

I see your concern. I haven't tried the test on the try bots before the fix, but
it failed consistently for me locally.

I've been looking for a way to wait for a failed load, but there is no such
notification one can monitor. Let me try another approach and see if it is
better.

+
+  // Load a regular web page, in which we will inject an iframe.
+  NavigateToFileURL(FILE_PATH_LITERAL("title2.html"));
+
+  // We expect to have two history entries, since we started off with navigation
+  // to "about:blank" and then navigated to "title2.html".
+  EXPECT_EQ(2, wc->GetController().GetEntryCount());
+
+  string16 expected_title(ASCIIToUTF16("done"));
+  content::TitleWatcher title_watcher(wc, expected_title);
+
+  wc->GetRenderViewHost()->ExecuteJavascriptInWebFrame(
+      string16(), ASCIIToUTF16(script));
+  EXPECT_EQ(expected_title, title_watcher.WaitAndGetTitle());
+
+  // Failed initial navigation of an iframe shouldn't be adding any history
+  // entries.
+  EXPECT_EQ(2, wc->GetController().GetEntryCount());
+}
+
 // Checks that the Link Doctor is not loaded when we receive an actual 404 page.
 IN_PROC_BROWSER_TEST_F(ErrorPageTest, Page404) {
   NavigateToURLAndWaitForTitle(