Merge "Form validation: Do not show validation bubble if the page is invisible." to M56 branch

third_party/WebKit/Source/core/html/HTMLFormControlElement.cpp

Index: third_party/WebKit/Source/core/html/HTMLFormControlElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLFormControlElement.cpp b/third_party/WebKit/Source/core/html/HTMLFormControlElement.cpp
index 127fa19138cea1169848e24bc7dca02a501f4ffd..d80eda69d7108be31395f47a976601610e1e3030 100644
--- a/third_party/WebKit/Source/core/html/HTMLFormControlElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLFormControlElement.cpp
@@ -454,7 +454,7 @@ void HTMLFormControlElement::findCustomValidationMessageTextDirection(
 
 void HTMLFormControlElement::updateVisibleValidationMessage() {
   Page* page = document().page();
-  if (!page)
+  if (!page || !page->isPageVisible())
     return;
   String message;
   if (layoutObject() && willValidate())