Add DelayNavigationThrottle

chrome/browser/chrome_content_browser_client.cc

Index: chrome/browser/chrome_content_browser_client.cc
diff --git a/chrome/browser/chrome_content_browser_client.cc b/chrome/browser/chrome_content_browser_client.cc
index 5d484d3b395bfa100a761302baa44b2b37c8e1c2..4cd86b9a5b21c41a6b869c72ba09de9e4de2a95d 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -47,6 +47,7 @@
 #include "chrome/browser/defaults.h"
 #include "chrome/browser/download/download_prefs.h"
 #include "chrome/browser/font_family_cache.h"
+#include "chrome/browser/loader/delay_navigation_throttle.h"
 #include "chrome/browser/media/webrtc/media_capture_devices_dispatcher.h"
 #include "chrome/browser/memory/chrome_memory_coordinator_delegate.h"
 #include "chrome/browser/metrics/chrome_browser_main_extra_parts_metrics.h"
@@ -3362,6 +3363,16 @@ ChromeContentBrowserClient::CreateThrottlesForNavigation(
     content::NavigationHandle* handle) {
   std::vector<std::unique_ptr<content::NavigationThrottle>> throttles;
 
+  // MetricsNavigationThrottle requires that it runs before NavigationThrottles
+  // that may delay or cancel navigations, so only NavigationThrottles that
+  // don't delay or cancel navigations (e.g. throttles that are only observing
+  // callbacks without affecting navigation behavior) should be added before
+  // MetricsNavigationThrottle.
+  if (handle->IsInMainFrame()) {
+    throttles.push_back(
+        page_load_metrics::MetricsNavigationThrottle::Create(handle));
+  }
+
 #if BUILDFLAG(ENABLE_PLUGINS)
   std::unique_ptr<content::NavigationThrottle> flash_url_throttle =
       FlashDownloadInterception::MaybeCreateThrottleFor(handle);
@@ -3369,11 +3380,6 @@ ChromeContentBrowserClient::CreateThrottlesForNavigation(
     throttles.push_back(std::move(flash_url_throttle));
 #endif
 
-  if (handle->IsInMainFrame()) {
-    throttles.push_back(
-        page_load_metrics::MetricsNavigationThrottle::Create(handle));
-  }
-
 #if defined(OS_ANDROID)
   // TODO(davidben): This is insufficient to integrate with prerender properly.
   // https://crbug.com/370595
@@ -3429,6 +3435,13 @@ ChromeContentBrowserClient::CreateThrottlesForNavigation(
       base::MakeUnique<extensions::ExtensionNavigationThrottle>(handle));
 #endif
 
+  if (handle->IsInMainFrame()) {

[Charlie Harrison, 2017/03/22 15:30:12]

optional: Since you already have a MaybeCreate* method, can move the
IsInMainFrame check there, so the throttle decides the policy.

[Bryan McQuade, 2017/03/22 18:00:01]

sure, good idea, done.

+    std::unique_ptr<content::NavigationThrottle> delay_navigation_throttle =
+        DelayNavigationThrottle::MaybeCreateThrottleFor(handle);
+    if (delay_navigation_throttle)
+      throttles.push_back(std::move(delay_navigation_throttle));
+  }
+
   return throttles;
 }