Avoid the long merge session throttle interstitial page for NTP on Chrome OS

chrome/browser/search/search.cc

Index: chrome/browser/search/search.cc
diff --git a/chrome/browser/search/search.cc b/chrome/browser/search/search.cc
index 645fecb9a52e535b344cc9554331c891695ddc61..d137683d1ae1a6773ba69b227f3a0dcdd1eed2e0 100644
--- a/chrome/browser/search/search.cc
+++ b/chrome/browser/search/search.cc
@@ -13,6 +13,7 @@
 #include "base/strings/string_split.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/browser_process.h"
+#include "chrome/browser/chromeos/login/signin/merge_session_throttling_utils.h"

[Marc Treib, 2016/04/21 08:32:12]

This should go into an #if defined(OS_CHROMEOS) block.

[afakhry, 2016/04/21 17:04:09]

Done.

 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/search/instant_service.h"
@@ -239,6 +240,23 @@ NewTabURLState IsValidNewTabURL(Profile* profile, const GURL& new_tab_url) {
   return NEW_TAB_URL_VALID;
 }
 
+#if defined(OS_CHROMEOS)
+
+// On Chrome OS, if the session hasn't merged yet, we need to avoid loading the
+// remote NTP because that will trigger showing the merge session throttle
+// interstitial page, which can show for 5+ seconds. crbug.com/591530.
+bool ShouldShowLocalNtpWhileMergeSessionInProgress(const GURL& url,
+                                                   Profile* profile) {
+  if (!merge_session_throttling_utils::ShouldDelayUrl(url) ||

[Marc Treib, 2016/04/21 08:32:12]

I'd move the "#if defined(OS_CHROMEOS)" here so that it covers this "if" only,
and rename the function to ShouldShowLocalNewTab. Then you won't need another
OS-specific block below.

[afakhry, 2016/04/21 17:04:09]

Done.

+      !merge_session_throttling_utils::ShouldDelayRequest(profile)) {
+    return false;
+  }
+
+  return true;
+}
+
+#endif  // defined(OS_CHROMEOS)
+
 // Used to look up the URL to use for the New Tab page. Also tracks how we
 // arrived at that URL so it can be logged with UMA.
 struct NewTabURLDetails {
@@ -259,6 +277,15 @@ struct NewTabURLDetails {
     GURL search_provider_url = TemplateURLRefToGURL(
         template_url->new_tab_url_ref(), UIThreadSearchTermsData(profile),
         false, false);
+
+#if defined(OS_CHROMEOS)
+    if (ShouldShowLocalNtpWhileMergeSessionInProgress(search_provider_url,
+                                                      profile)) {
+      // Force load the local NTP if the merge session is not complete.
+      return NewTabURLDetails(local_url, NEW_TAB_URL_VALID);
+    }
+#endif  // defined(OS_CHROMEOS)
+
     NewTabURLState state = IsValidNewTabURL(profile, search_provider_url);
     switch (state) {
       case NEW_TAB_URL_VALID: