PasswordAutofillAgent: do not provisionally save forms in NULL frames

components/autofill/content/renderer/password_autofill_agent.cc

Index: components/autofill/content/renderer/password_autofill_agent.cc
diff --git a/components/autofill/content/renderer/password_autofill_agent.cc b/components/autofill/content/renderer/password_autofill_agent.cc
index ae858fec29733ff3ca893828ba6173d7753ba4a0..8797971ab7c53c8074243fe9905c11454d2fca5d 100644
--- a/components/autofill/content/renderer/password_autofill_agent.cc
+++ b/components/autofill/content/renderer/password_autofill_agent.cc
@@ -533,8 +533,10 @@ bool PasswordAutofillAgent::TextDidChangeInTextField(
     // handlers run, so save away a copy of the password in case it gets lost.
     // To honor the user having explicitly cleared the password, even an empty
     // password will be saved here.
-    ProvisionallySavePassword(
-        element.document().frame(), element.form(), RESTRICTION_NONE);
+    if (blink::WebLocalFrame* element_frame = element.document().frame()) {
+      ProvisionallySavePassword(
+          element_frame, element.form(), RESTRICTION_NONE);
+    }
 
     PasswordToLoginMap::iterator iter = password_to_username_.find(element);
     if (iter != password_to_username_.end()) {