Destroy (Password)AutofillAgent safely

components/autofill/content/renderer/password_generation_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_generation_agent.h"
 
 #include <memory>
 
 #include "base/command_line.h"
 #include "base/logging.h"
@@ skipping 161 matching lines @@
     if (editing_popup_shown_) {
       password_generation::LogPasswordGenerationEvent(
           password_generation::EDITING_POPUP_SHOWN);
     }
     editing_popup_shown_ = false;
   }
 
   FindPossibleGenerationForm();
 }
 
+void PasswordGenerationAgent::OnDestruct() {
+  base::ThreadTaskRunnerHandle::Get()->DeleteSoon(FROM_HERE, this);
+}
+
 void PasswordGenerationAgent::OnDynamicFormsSeen() {
   FindPossibleGenerationForm();
 }
 
 void PasswordGenerationAgent::FindPossibleGenerationForm() {
-  if (!enabled_)
+  if (!enabled_ || !render_frame())
     return;
 
   // We don't want to generate passwords if the browser won't store or sync
   // them.
   if (!ShouldAnalyzeDocument())
     return;
 
   // If we have already found a signup form for this page, no need to continue.
   if (generation_form_data_)
     return;
@@ skipping 32 matching lines @@
   if (!possible_account_creation_forms_.empty()) {
     VLOG(2) << possible_account_creation_forms_.size()
             << " possible account creation forms deteceted";
     DetermineGenerationElement();
   }
 }
 
 bool PasswordGenerationAgent::ShouldAnalyzeDocument() const {
   // Make sure that this security origin is allowed to use password manager.
   // Generating a password that can't be saved is a bad idea.
-  blink::WebSecurityOrigin origin =
-      render_frame()->GetWebFrame()->document().getSecurityOrigin();
-  if (!origin.canAccessPasswordManager()) {
+  if (!render_frame() ||
+      !render_frame()
+           ->GetWebFrame()
+           ->document()
+           .getSecurityOrigin()
+           .canAccessPasswordManager()) {
     VLOG(1) << "No PasswordManager access";
     return false;
   }
 
   return true;
 }
 
 bool PasswordGenerationAgent::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(PasswordGenerationAgent, message)
@@ skipping 15 matching lines @@
   DetermineGenerationElement();
 }
 
 void PasswordGenerationAgent::OnPasswordAccepted(
     const base::string16& password) {
   password_is_generated_ = true;
   password_generation::LogPasswordGenerationEvent(
       password_generation::PASSWORD_ACCEPTED);
   for (auto& password_element : generation_form_data_->password_elements) {
     password_element.setValue(password, true /* sendEvents */);
+    // setValue() above may have resulted in JavaScript closing the frame.
+    if (!render_frame())
+      return;
     password_element.setAutofilled(true);
     // Needed to notify password_autofill_agent that the content of the field
     // has changed. Without this we will overwrite the generated
     // password with an Autofilled password when saving.
     // https://crbug.com/493455
     password_agent_->UpdateStateForTextChange(password_element);
     // Advance focus to the next input field. We assume password fields in
     // an account creation form are always adjacent.
     render_frame()->GetRenderView()->GetWebView()->advanceFocus(false);
   }
@@ skipping 185 matching lines @@
     // Password isn't generated and there are fewer than kMaximumOfferSize
     // characters typed, so keep offering the password. Note this function
     // will just keep the previous popup if one is already showing.
     ShowGenerationPopup();
   }
 
   return true;
 }
 
 void PasswordGenerationAgent::ShowGenerationPopup() {
+  if (!render_frame())
+    return;
   Send(new AutofillHostMsg_ShowPasswordGenerationPopup(
       routing_id(),
       render_frame()->GetRenderView()->ElementBoundsInWindow(
           generation_element_),
       generation_element_.maxLength(),
       generation_element_.nameForAutofill(),
       is_manually_triggered_,
       *generation_form_data_->form));
   generation_popup_shown_ = true;
 }
 
 void PasswordGenerationAgent::ShowEditingPopup() {
+  if (!render_frame())
+    return;
   Send(new AutofillHostMsg_ShowPasswordEditingPopup(
            routing_id(),
            render_frame()->GetRenderView()->ElementBoundsInWindow(
                generation_element_),
            *generation_form_data_->form));
   editing_popup_shown_ = true;
 }
 
 void PasswordGenerationAgent::HidePopup() {
   Send(new AutofillHostMsg_HidePasswordGenerationPopup(routing_id()));
 }
 
 void PasswordGenerationAgent::OnUserTriggeredGeneratePassword() {
-  if (last_focused_password_element_.isNull())
+  if (last_focused_password_element_.isNull() || !render_frame())
     return;
 
   blink::WebFormElement form = last_focused_password_element_.form();
   std::unique_ptr<PasswordForm> password_form;
   std::vector<blink::WebFormControlElement> control_elements;
   if (!form.isNull()) {
     password_form = CreatePasswordFormFromWebForm(form, nullptr, nullptr);
     control_elements = form_util::ExtractAutofillableElementsInForm(form);
   } else {
     const blink::WebFrame& frame = *render_frame()->GetWebFrame();
@@ skipping 14 matching lines @@
   GetAccountCreationPasswordFields(control_elements, &password_elements);
   password_elements = FindPasswordElementsForGeneration(
       password_elements, last_focused_password_element_.nameForAutofill());
   generation_form_data_.reset(new AccountCreationFormData(
       make_linked_ptr(password_form.release()), password_elements));
   is_manually_triggered_ = true;
   ShowGenerationPopup();
 }
 
 }  // namespace autofill