Add a DCHECK for NULL frame pointers in PasswordAutofillAgent

components/autofill/content/renderer/password_autofill_agent.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/autofill/content/renderer/password_autofill_agent.h"
 
 #include "base/bind.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram.h"
@@ skipping 654 matching lines @@
   }
 }
 
 blink::WebFrame* PasswordAutofillAgent::CurrentOrChildFrameWithSavedForms(
     const blink::WebFrame* current_frame) {
   for (FrameToPasswordFormMap::const_iterator it =
            provisionally_saved_forms_.begin();
        it != provisionally_saved_forms_.end();
        ++it) {
     blink::WebFrame* form_frame = it->first;
+    DCHECK(form_frame);

[Ilya Sherman, 2014/08/01 18:42:39]

This is dereferenced on line 683 below, so I'm not sure how much value the
DCHECK adds.

[vabr (Chromium), 2014/08/01 19:10:13]

Fair point, I removed it.

     // The check that the returned frame is related to |current_frame| is mainly
     // for double-checking. There should not be any unrelated frames in
     // |provisionally_saved_forms_|, because the map is cleared after
     // navigation. If there are reasons to remove this check in the future and
     // keep just the first frame found, it might be a good idea to add a UMA
     // statistic or a similar check on how many frames are here to choose from.
     if (current_frame == form_frame ||
         current_frame->findChildByName(form_frame->assignedName())) {
       return form_frame;
     }
@@ skipping 417 matching lines @@
   if (!password->suggestedValue().isEmpty()) {
       password->setSuggestedValue(blink::WebString());
       password->setAutofilled(was_password_autofilled_);
   }
 }
 
 void PasswordAutofillAgent::ProvisionallySavePassword(
     blink::WebLocalFrame* frame,
     const blink::WebFormElement& form,
     ProvisionallySaveRestriction restriction) {
+  DCHECK(frame);
   scoped_ptr<PasswordForm> password_form(CreatePasswordForm(form));
   if (!password_form || (restriction == RESTRICTION_NON_EMPTY_PASSWORD &&
                          password_form->password_value.empty() &&
                          password_form->new_password_value.empty())) {
     return;
   }
   provisionally_saved_forms_[frame].reset(password_form.release());
 }
 
 }  // namespace autofill