Mixed Content: Make MixedContentChecker completely static.

Source/core/html/HTMLFormElement.cpp

Index: Source/core/html/HTMLFormElement.cpp
diff --git a/Source/core/html/HTMLFormElement.cpp b/Source/core/html/HTMLFormElement.cpp
index 013dfd394be8dbef75ae85657bcc183e80b7aa84..4dd0ee37545da6e428d22353f467e0702bcc69e2 100644
--- a/Source/core/html/HTMLFormElement.cpp
+++ b/Source/core/html/HTMLFormElement.cpp
@@ -442,13 +442,9 @@ void HTMLFormElement::scheduleFormSubmission(PassRefPtrWillBeRawPtr<FormSubmissi
     if (!targetFrame->page())
         return;
 
-    if (MixedContentChecker::isMixedContent(document().securityOrigin(), submission->action())) {
+    UseCounter::count(document(), UseCounter::FormsSubmitted);
+    if (MixedContentChecker::checkFormAction(document().frame(), submission->action()))
         UseCounter::count(document(), UseCounter::MixedContentFormsSubmitted);
-        if (!document().frame()->loader().mixedContentChecker()->canSubmitToInsecureForm(document().securityOrigin(), submission->action()))
-            return;
-    } else {
-        UseCounter::count(document(), UseCounter::FormsSubmitted);
-    }
 
     submission->setReferrer(Referrer(document().outgoingReferrer(), document().referrerPolicy()));
     submission->setOrigin(document().outgoingOrigin());
@@ -522,8 +518,7 @@ void HTMLFormElement::parseAttribute(const QualifiedName& name, const AtomicStri
         // If the new action attribute is pointing to insecure "action" location from a secure page
         // it is marked as "passive" mixed content.
         KURL actionURL = document().completeURL(m_attributes.action().isEmpty() ? document().url().string() : m_attributes.action());
-        if (document().frame() && MixedContentChecker::isMixedContent(document().securityOrigin(), actionURL))
-            document().frame()->loader().mixedContentChecker()->canSubmitToInsecureForm(document().securityOrigin(), actionURL);
+        MixedContentChecker::checkFormAction(document().frame(), actionURL);
     } else if (name == targetAttr)
         m_attributes.setTarget(value);
     else if (name == methodAttr)