[Android] Verify FormData in TryToShowKeyboardReplacingSurface

(cherry picked from commit 5021828)

Fixed: 1449661
Change-Id: I406a275889a6973a4f36192b2b56f995b5b48341
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4573388
Commit-Queue: Adem Derinel <derinel@google.com>
Code-Coverage: Findit <findit-for-me@appspot.gserviceaccount.com>
Reviewed-by: Vasilii Sukhanov <vasilii@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#1150491}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4579594
Cr-Commit-Position: refs/branch-heads/5790@{#251}
Cr-Branched-From: 1d71a33-refs/heads/main@{#1148114}

components/autofill/content/renderer/password_autofill_agent.cc

@@ -1067,6 +1067,7 @@ bool PasswordAutofillAgent::TryToShowKeyboardReplacingSurface(
       form.IsNull() ? GetFormDataFromUnownedInputElements()
                     : GetFormDataFromWebForm(form);
   bool is_webauthn_form =
+      form_data &&
       std::any_of(form_data->fields.begin(), form_data->fields.end(),
                   autofill::FieldHasWebAuthnAutocompleteAttribute);
   GetPasswordManagerDriver().ShowKeyboardReplacingSurface(