Add a chrome://interstitials page.

chrome/browser/ui/webui/chrome_web_ui_controller_factory.cc

Index: chrome/browser/ui/webui/chrome_web_ui_controller_factory.cc
diff --git a/chrome/browser/ui/webui/chrome_web_ui_controller_factory.cc b/chrome/browser/ui/webui/chrome_web_ui_controller_factory.cc
index 58456aaa07b64769a602d3b36fbee5b0f952ffb0..12257354e3bdc53255c33e82040178ad4f336071 100644
--- a/chrome/browser/ui/webui/chrome_web_ui_controller_factory.cc
+++ b/chrome/browser/ui/webui/chrome_web_ui_controller_factory.cc
@@ -35,6 +35,7 @@
 #include "chrome/browser/ui/webui/identity_internals_ui.h"
 #include "chrome/browser/ui/webui/inspect_ui.h"
 #include "chrome/browser/ui/webui/instant_ui.h"
+#include "chrome/browser/ui/webui/interstitials/interstitial_ui.h"
 #include "chrome/browser/ui/webui/invalidations_ui.h"
 #include "chrome/browser/ui/webui/memory_internals/memory_internals_ui.h"
 #include "chrome/browser/ui/webui/net_internals/net_internals_ui.h"
@@ -290,6 +291,8 @@ WebUIFactoryFunction GetWebUIFactoryFunction(WebUI* web_ui,
     return &NewWebUI<HistoryUI>;
   if (url.host() == chrome::kChromeUIInstantHost)
     return &NewWebUI<InstantUI>;
+  if (url.host() == chrome::kChromeUIInterstitialHost)
+    return &NewWebUI<InterstitialUI>;
   if (url.host() == chrome::kChromeUIInvalidationsHost)
     return &NewWebUI<InvalidationsUI>;
   if (url.host() == chrome::kChromeUISupervisedUserPassphrasePageHost)