override chrome:// URLs via extensions.

chrome/common/notification_type.h

Index: chrome/common/notification_type.h
diff --git a/chrome/common/notification_type.h b/chrome/common/notification_type.h
index ba74687542393f15e35f4371d0e6bd5dc0c07c9a..7c7140f5904afea70eb3cf6a5c2e808527022ae9 100644
--- a/chrome/common/notification_type.h
+++ b/chrome/common/notification_type.h
@@ -631,6 +631,10 @@ class NotificationType {
     // an ExtensionHost* and the source is a Profile*.
     EXTENSION_HOST_DESTROYED,
 
+    // Send by an ExtensionHost when it finished its initial page load.
+    // The details are an ExtensionHost* and the source is a Profile*.
+    EXTENSION_HOST_DID_STOP_LOADING,
+
     // Sent after an extension render process is created and fully functional.
     // The details are an ExtensionHost*.
     EXTENSION_PROCESS_CREATED,