Report nav timing 2 instance as soon as it's requested.

third_party/WebKit/Source/core/loader/DocumentLoader.cpp

Index: third_party/WebKit/Source/core/loader/DocumentLoader.cpp
diff --git a/third_party/WebKit/Source/core/loader/DocumentLoader.cpp b/third_party/WebKit/Source/core/loader/DocumentLoader.cpp
index c527aa4cdb4991379ed1ef089b62b86059076e64..7cc002b19ced23d54c58776990f6616b248559ec 100644
--- a/third_party/WebKit/Source/core/loader/DocumentLoader.cpp
+++ b/third_party/WebKit/Source/core/loader/DocumentLoader.cpp
@@ -29,6 +29,7 @@
 
 #include "core/loader/DocumentLoader.h"
 
+#include <memory>
 #include "core/dom/Document.h"
 #include "core/dom/WeakIdentifierMap.h"
 #include "core/events/Event.h"
@@ -65,6 +66,7 @@
 #include "platform/mhtml/ArchiveResource.h"
 #include "platform/network/ContentSecurityPolicyResponseHeaders.h"
 #include "platform/network/HTTPParsers.h"
+#include "platform/network/ResourceTimingInfo.h"
 #include "platform/network/mime/MIMETypeRegistry.h"
 #include "platform/plugins/PluginData.h"
 #include "platform/weborigin/SchemeRegistry.h"
@@ -74,7 +76,6 @@
 #include "wtf/Assertions.h"
 #include "wtf/AutoReset.h"
 #include "wtf/text/WTFString.h"
-#include <memory>
 
 namespace blink {
 
@@ -163,6 +164,7 @@ unsigned long DocumentLoader::mainResourceIdentifier() const {
 }
 
 ResourceTimingInfo* DocumentLoader::getNavigationTimingInfo() const {
+  DCHECK(fetcher());
   return fetcher()->getNavigationTimingInfo();
 }