Use an MutationObserver to check when a password form disappears after XHR

third_party/WebKit/Source/web/WebDocument.cpp

Index: third_party/WebKit/Source/web/WebDocument.cpp
diff --git a/third_party/WebKit/Source/web/WebDocument.cpp b/third_party/WebKit/Source/web/WebDocument.cpp
index 110117fbe358318db101657537c71f416e974150..9e65b38221b76c1f7cc27639e084ea3201e53776 100644
--- a/third_party/WebKit/Source/web/WebDocument.cpp
+++ b/third_party/WebKit/Source/web/WebDocument.cpp
@@ -39,6 +39,7 @@
 #include "core/dom/DocumentStatisticsCollector.h"
 #include "core/dom/DocumentType.h"
 #include "core/dom/Element.h"
+#include "core/dom/FormElementObserver.h"
 #include "core/dom/StyleEngine.h"
 #include "core/events/Event.h"
 #include "core/frame/WebLocalFrameBase.h"
@@ -48,6 +49,7 @@
 #include "core/html/HTMLElement.h"
 #include "core/html/HTMLFormElement.h"
 #include "core/html/HTMLHeadElement.h"
+#include "core/html/HTMLInputElement.h"
 #include "core/html/HTMLLinkElement.h"
 #include "core/layout/LayoutObject.h"
 #include "core/layout/api/LayoutAPIShim.h"
@@ -65,6 +67,8 @@
 #include "public/web/WebElement.h"
 #include "public/web/WebElementCollection.h"
 #include "public/web/WebFormElement.h"
+#include "public/web/WebFormElementObserverCallback.h"
+#include "public/web/WebInputElement.h"
 #include "v8/include/v8.h"
 
 namespace blink {
@@ -289,6 +293,20 @@ WebDistillabilityFeatures WebDocument::DistillabilityFeatures() {
   return DocumentStatisticsCollector::CollectStatistics(*Unwrap<Document>());
 }
 
+void WebDocument::ObserveFormElement(
+    WebFormElement& element,
+    std::unique_ptr<WebFormElementObserverCallback> callback) {
+  Unwrap<Document>()->GetFormElementObserver()->Observe(
+      *element.Unwrap<HTMLFormElement>(), std::move(callback));
+}
+
+void WebDocument::ObserveFormElement(
+    WebInputElement& element,
+    std::unique_ptr<WebFormElementObserverCallback> callback) {
+  Unwrap<Document>()->GetFormElementObserver()->Observe(
+      *element.Unwrap<HTMLInputElement>(), std::move(callback));
+}
+
 WebDocument::WebDocument(Document* elem) : WebNode(elem) {}
 
 DEFINE_WEB_NODE_TYPE_CASTS(WebDocument, ConstUnwrap<Node>()->IsDocumentNode());