Style tag in an XHR's responseXML shouldn't make the responseXML be null.

third_party/WebKit/Source/core/dom/Document.cpp

Index: third_party/WebKit/Source/core/dom/Document.cpp
diff --git a/third_party/WebKit/Source/core/dom/Document.cpp b/third_party/WebKit/Source/core/dom/Document.cpp
index 4c5698d9b2f75ecd9beedc41ca75cfde121445cf..77e717c5b7fd735398744909d05ab7051eccba82 100644
--- a/third_party/WebKit/Source/core/dom/Document.cpp
+++ b/third_party/WebKit/Source/core/dom/Document.cpp
@@ -3032,9 +3032,6 @@ void Document::ImplicitClose() {
 
   load_event_progress_ = kLoadEventInProgress;
 
-  ScriptableDocumentParser* parser = GetScriptableDocumentParser();
-  well_formed_ = parser && parser->WellFormed();
-
   // We have to clear the parser, in case someone document.write()s from the
   // onLoad event handler, as in Radar 3206524.
   DetachParser();
@@ -5501,6 +5498,9 @@ void Document::FinishedParsing() {
   // a queued task, which will do a checkpoint anyway. https://crbug.com/425790
   Microtask::PerformCheckpoint(V8PerIsolateData::MainThreadIsolate());
 
+  ScriptableDocumentParser* parser = GetScriptableDocumentParser();
+  well_formed_ = parser && parser->WellFormed();
+
   if (LocalFrame* frame = this->GetFrame()) {
     // Don't update the layout tree if we haven't requested the main resource
     // yet to avoid adding extra latency. Note that the first layout tree update