Add WaitForInterstitialReady to browser_test_utils.

content/public/test/browser_test_utils.cc

Index: content/public/test/browser_test_utils.cc
diff --git a/content/public/test/browser_test_utils.cc b/content/public/test/browser_test_utils.cc
index 89dd3430e96dbca0330338b1fc035951d215e908..bc341b37057d5aaf17bfb541c14fccc95b8a23d1 100644
--- a/content/public/test/browser_test_utils.cc
+++ b/content/public/test/browser_test_utils.cc
@@ -21,6 +21,7 @@
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/dom_operation_notification_details.h"
 #include "content/public/browser/histogram_fetcher.h"
+#include "content/public/browser/interstitial_page.h"

[mattm, 2015/01/22 04:51:27]

no longer needed

[meacer, 2015/01/22 18:31:37]

Done.

 #include "content/public/browser/navigation_entry.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_types.h"
@@ -723,6 +724,28 @@ void RunTaskAndWaitForInterstitialDetach(content::WebContents* web_contents,
   loop_runner->Run();
 }
 
+bool WaitForRenderFrameReady(RenderFrameHost* rfh) {
+  if (!rfh)
+    return false;
+  std::string result;
+  EXPECT_TRUE(
+      content::ExecuteScriptAndExtractString(
+          rfh,
+          "(function() {"
+          "  var done = false;"
+          "  function checkState() {"
+          "    if (!done && document.readyState == 'complete') {"
+          "      done = true;"
+          "      window.domAutomationController.send('pageLoadComplete');"
+          "    }"
+          "  }"
+          "  checkState();"
+          "  document.addEventListener('readystatechange', checkState);"

[Paweł Hajdan Jr., 2015/01/22 15:43:10]

I might be wrong (not a JS/DOM expert), but shouldn't we add the event listener
first? I wonder if there might be a race if the condition becomes true right
between checkState() and addEventListener() calls.

[mmenke, 2015/01/22 15:53:25]

Javascript and the DOM are essentially single-threaded.  The DOM can't change
and an event can't happen in the middle of the execution of Javascript running.

That having been said, I'm certainly fine with changing order, it just doesn't
matter, either way, in this case.

[mmenke, 2015/01/22 15:55:00]

That is, they can't change except as a result of a Javascript function call, of
course.

+          "})();",
+          &result));
+  return result == "pageLoadComplete";
+}
+
 TitleWatcher::TitleWatcher(WebContents* web_contents,
                            const base::string16& expected_title)
     : WebContentsObserver(web_contents),