Local NTP tests cleanup: Rewrite LoadsIframe to use the real local NTP

Before, it used local_ntp_browsertest.html instead, for no good reason.

Bug: 788166
Change-Id: Iba4fe5c06eab1bc9fafebe6f528955c208c24359
Reviewed-on: https://chromium-review.googlesource.com/787897Reviewed-by: Chris Pickel <sfiera@chromium.org>
Commit-Queue: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#519737}

chrome/browser/ui/search/local_ntp_browsertest.cc

@@ -542,26 +542,10 @@ content::RenderFrameHost* GetMostVisitedIframe(content::WebContents* tab) {
 
 }  // namespace
 
-IN_PROC_BROWSER_TEST_F(LocalNTPJavascriptTest, LoadsIframe) {
-  content::WebContents* active_tab = local_ntp_test_utils::OpenNewTab(
-      browser(), GURL(chrome::kChromeUINewTabURL));
-  ASSERT_TRUE(search::IsInstantNTP(active_tab));
-
-  content::DOMMessageQueue msg_queue;
-
-  bool result = false;
-  ASSERT_TRUE(instant_test_utils::GetBoolFromJS(
-      active_tab, "!!setupAdvancedTest(true)", &result));
-  ASSERT_TRUE(result);
-
-  // Wait for the MV iframe to load.
-  std::string message;
-  // First get rid of the "true" message from the GetBoolFromJS call above.
-  ASSERT_TRUE(msg_queue.PopMessage(&message));
-  ASSERT_EQ("true", message);
-  // Now wait for the "loaded" message.
-  ASSERT_TRUE(msg_queue.WaitForMessage(&message));
-  ASSERT_EQ("\"loaded\"", message);
+IN_PROC_BROWSER_TEST_F(LocalNTPTest, LoadsIframe) {
+  content::WebContents* active_tab =
+      local_ntp_test_utils::OpenNewTab(browser(), GURL("about:blank"));
+  NavigateToNTPAndWaitUntilLoaded();
 
   // Get the iframe and check that the tiles loaded correctly.
   content::RenderFrameHost* iframe = GetMostVisitedIframe(active_tab);

chrome/test/data/local_ntp/local_ntp_browsertest.js

@@ -93,18 +93,8 @@ function initLocalNTP(isGooglePage) {
 // Advanced tests are controlled from the native side. The helpers here are
 // called from native code to set up the page and to check results.
 
-function handlePostMessage(event) {
-  if (event.data.cmd == 'loaded') {
-    domAutomationController.send('loaded');
-  }
-}
-
-
-function setupAdvancedTest(opt_waitForIframeLoaded) {
-  if (opt_waitForIframeLoaded) {
-    window.addEventListener('message', handlePostMessage);
-  }
 
+function setupAdvancedTest() {
   setUpPage('local-ntp-template');
   initLocalNTP(/*isGooglePage=*/true);