[Password manager] Temporarily add some CHECKs to investigate a crash

Add some CHECKs to see if some of the hypotheses in http://crbug.com/486931#c3 (however unlikely they seem) could be right.
This is in line with https://www.chromium.org/developers/coding-style#TOC-CHECK-DCHECK-and-NOTREACHED-.

BUG=486931

Review URL: https://codereview.chromium.org/1139863003

Cr-Commit-Position: refs/heads/master@{#329393}

chrome/browser/ui/passwords/manage_passwords_state.cc

@@ -149,7 +149,8 @@ void ManagePasswordsState::OnAutomaticPasswordSave(
 
 void ManagePasswordsState::OnPasswordAutofilled(
     const PasswordFormMap& password_form_map) {
-  DCHECK(!password_form_map.empty());
+  // TODO(vabr): Revert back to DCHECK once http://crbug.com/486931 is fixed.
+  CHECK(!password_form_map.empty());
   ClearData();
   if (password_form_map.begin()->second->IsPublicSuffixMatch()) {
     // Don't show the UI for PSL matched passwords. They are not stored for this

components/autofill/core/common/password_form.cc

@@ -76,13 +76,17 @@ PasswordForm::PasswordForm()
       generation_upload_status(NO_SIGNAL_SENT),
       skip_zero_click(false),
       layout(Layout::LAYOUT_OTHER),
-      was_parsed_using_autofill_predictions(false) {
+      was_parsed_using_autofill_predictions(false),
+      is_alive(true) {
 }
 
 PasswordForm::~PasswordForm() {
+  CHECK(is_alive);
+  is_alive = false;
 }
 
 bool PasswordForm::IsPublicSuffixMatch() const {
+  CHECK(is_alive);
   return !original_signon_realm.empty();
 }
 

components/autofill/core/common/password_form.h

@@ -265,6 +265,9 @@ struct PasswordForm {
   // If true, this form was parsed using Autofill predictions.
   bool was_parsed_using_autofill_predictions;
 
+  // TODO(vabr): Remove |is_alive| once http://crbug.com/486931 is fixed.
+  bool is_alive;  // Set on construction, reset on destruction.
+
   // Returns true if this match was found using public suffix matching.
   bool IsPublicSuffixMatch() const;