// 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 <stddef.h>

#include <memory>
#include <string>
#include <utility>

#include "base/bind.h"
#include "base/command_line.h"
#include "base/i18n/case_conversion.h"
#include "base/memory/linked_ptr.h"
#include "base/message_loop/message_loop.h"
#include "base/metrics/field_trial.h"
#include "base/metrics/histogram_macros.h"
#include "base/strings/utf_string_conversions.h"
#include "build/build_config.h"
#include "components/autofill/content/common/autofill_messages.h"
#include "components/autofill/content/renderer/form_autofill_util.h"
#include "components/autofill/content/renderer/password_form_conversion_utils.h"
#include "components/autofill/content/renderer/renderer_save_password_progress_logger.h"
#include "components/autofill/core/common/autofill_constants.h"
#include "components/autofill/core/common/autofill_switches.h"
#include "components/autofill/core/common/autofill_util.h"
#include "components/autofill/core/common/form_field_data.h"
#include "components/autofill/core/common/password_form.h"
#include "components/autofill/core/common/password_form_fill_data.h"
#include "content/public/renderer/document_state.h"
#include "content/public/renderer/navigation_state.h"
#include "content/public/renderer/render_frame.h"
#include "content/public/renderer/render_view.h"
#include "third_party/WebKit/public/platform/WebSecurityOrigin.h"
#include "third_party/WebKit/public/platform/WebVector.h"
#include "third_party/WebKit/public/web/WebAutofillClient.h"
#include "third_party/WebKit/public/web/WebDocument.h"
#include "third_party/WebKit/public/web/WebElement.h"
#include "third_party/WebKit/public/web/WebFormElement.h"
#include "third_party/WebKit/public/web/WebInputEvent.h"
#include "third_party/WebKit/public/web/WebLocalFrame.h"
#include "third_party/WebKit/public/web/WebNode.h"
#include "third_party/WebKit/public/web/WebUserGestureIndicator.h"
#include "third_party/WebKit/public/web/WebView.h"
#include "ui/base/page_transition_types.h"
#include "ui/events/keycodes/keyboard_codes.h"
#include "url/gurl.h"

namespace autofill {
namespace {

// The size above which we stop triggering autocomplete.
static const size_t kMaximumTextSizeForAutocomplete = 1000;

// Experiment information
const char kFillOnAccountSelectFieldTrialName[] = "FillOnAccountSelect";
const char kFillOnAccountSelectFieldTrialEnabledWithHighlightGroup[] =
    "EnableWithHighlight";
const char kFillOnAccountSelectFieldTrialEnabledWithNoHighlightGroup[] =
    "EnableWithNoHighlight";
const char kDummyUsernameField[] = "anonymous_username";
const char kDummyPasswordField[] = "anonymous_password";

// Maps element names to the actual elements to simplify form filling.
typedef std::map<base::string16, blink::WebInputElement> FormInputElementMap;

// Use the shorter name when referencing SavePasswordProgressLogger::StringID
// values to spare line breaks. The code provides enough context for that
// already.
typedef SavePasswordProgressLogger Logger;

typedef std::vector<FormInputElementMap> FormElementsList;

bool FillDataContainsFillableUsername(const PasswordFormFillData& fill_data) {
  return !fill_data.username_field.name.empty() &&
         (!fill_data.additional_logins.empty() ||
          !fill_data.username_field.value.empty());
}

// Returns true if password form has username and password fields with either
// same or no name and id attributes supplied.
bool DoesFormContainAmbiguousOrEmptyNames(
    const PasswordFormFillData& fill_data) {
  return (fill_data.username_field.name == fill_data.password_field.name) ||
         (fill_data.password_field.name ==
              base::ASCIIToUTF16(kDummyPasswordField) &&
          (!FillDataContainsFillableUsername(fill_data) ||
           fill_data.username_field.name ==
               base::ASCIIToUTF16(kDummyUsernameField)));
}

bool IsPasswordField(const FormFieldData& field) {
  return (field.form_control_type == "password");
}

// Returns true if any password field within |control_elements| is supplied with
// either |autocomplete='current-password'| or |autocomplete='new-password'|
// attribute.
bool HasPasswordWithAutocompleteAttribute(
    const std::vector<blink::WebFormControlElement>& control_elements) {
  for (const blink::WebFormControlElement& control_element : control_elements) {
    if (!control_element.hasHTMLTagName("input"))
      continue;

    const blink::WebInputElement input_element =
        control_element.toConst<blink::WebInputElement>();
    if (input_element.isPasswordField() &&
        (HasAutocompleteAttributeValue(input_element, "current-password") ||
         HasAutocompleteAttributeValue(input_element, "new-password")))
      return true;
  }

  return false;
}

// Returns the |field|'s autofillable name. If |ambiguous_or_empty_names| is set
// to true returns a dummy name instead.
base::string16 FieldName(const FormFieldData& field,
                         bool ambiguous_or_empty_names) {
  return ambiguous_or_empty_names
             ? IsPasswordField(field) ? base::ASCIIToUTF16(kDummyPasswordField)
                                      : base::ASCIIToUTF16(kDummyUsernameField)
             : field.name;
}

bool IsUnownedPasswordFormVisible(blink::WebFrame* frame,
                                  const GURL& action,
                                  const GURL& origin,
                                  const FormData& form_data,
                                  const FormsPredictionsMap& form_predictions) {
  std::unique_ptr<PasswordForm> unowned_password_form(
      CreatePasswordFormFromUnownedInputElements(*frame, nullptr,
                                                 &form_predictions));
  if (!unowned_password_form)
    return false;
  std::vector<blink::WebFormControlElement> control_elements =
      form_util::GetUnownedAutofillableFormFieldElements(
          frame->document().all(), nullptr);
  if (!form_util::IsSomeControlElementVisible(control_elements))
    return false;

#if !defined(OS_MACOSX) && !defined(OS_ANDROID)
  const bool action_is_empty = action == origin;
  bool forms_are_same =
      action_is_empty ? form_data.SameFormAs(unowned_password_form->form_data)
                      : action == unowned_password_form->action;
  return forms_are_same;
#else  // OS_MACOSX or OS_ANDROID
  return action == unowned_password_form->action;
#endif
}

// Utility function to find the unique entry of |control_elements| for the
// specified input |field|. On successful find, adds it to |result| and returns
// |true|. Otherwise clears the references from each |HTMLInputElement| from
// |result| and returns |false|.
bool FindFormInputElement(
    const std::vector<blink::WebFormControlElement>& control_elements,
    const FormFieldData& field,
    bool ambiguous_or_empty_names,
    FormInputElementMap* result) {
  // Match the first input element, if any.
  bool found_input = false;
  bool is_password_field = IsPasswordField(field);
  bool does_password_field_has_ambigous_or_empty_name =
      ambiguous_or_empty_names && is_password_field;
  bool ambiguous_and_multiple_password_fields_with_autocomplete =
      does_password_field_has_ambigous_or_empty_name &&
      HasPasswordWithAutocompleteAttribute(control_elements);
  base::string16 field_name = FieldName(field, ambiguous_or_empty_names);
  for (const blink::WebFormControlElement& control_element : control_elements) {
    if (!ambiguous_or_empty_names &&
        control_element.nameForAutofill() != field_name) {
      continue;
    }

    if (!control_element.hasHTMLTagName("input"))
      continue;

    // Only fill saved passwords into password fields and usernames into text
    // fields.
    const blink::WebInputElement input_element =
        control_element.toConst<blink::WebInputElement>();
    if (input_element.isPasswordField() != is_password_field)
      continue;

    // For change password form with ambiguous or empty names keep only the
    // first password field having |autocomplete='current-password'| attribute
    // set. Also make sure we avoid keeping password fields having
    // |autocomplete='new-password'| attribute set.
    if (ambiguous_and_multiple_password_fields_with_autocomplete &&
        !HasAutocompleteAttributeValue(input_element, "current-password")) {
      continue;
    }

    // Check for a non-unique match.
    if (found_input) {
      // For change password form keep only the first password field entry.
      if (does_password_field_has_ambigous_or_empty_name) {
        if (!form_util::IsWebNodeVisible((*result)[field_name])) {
          // If a previously chosen field was invisible then take the current
          // one.
          (*result)[field_name] = input_element;
        }
        continue;
      }

      found_input = false;
      break;
    }

    (*result)[field_name] = input_element;
    found_input = true;
  }

  // A required element was not found. This is not the right form.
  // Make sure no input elements from a partially matched form in this
  // iteration remain in the result set.
  // Note: clear will remove a reference from each InputElement.
  if (!found_input) {
    result->clear();
    return false;
  }

  return true;
}

bool ShouldFillOnAccountSelect() {
  std::string group_name =
      base::FieldTrialList::FindFullName(kFillOnAccountSelectFieldTrialName);

  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
          switches::kDisableFillOnAccountSelect)) {
    return false;
  }

  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
          switches::kEnableFillOnAccountSelect) ||
      base::CommandLine::ForCurrentProcess()->HasSwitch(
          switches::kEnableFillOnAccountSelectNoHighlighting)) {
    return true;
  }

  return group_name ==
             kFillOnAccountSelectFieldTrialEnabledWithHighlightGroup ||
         group_name ==
             kFillOnAccountSelectFieldTrialEnabledWithNoHighlightGroup;
}

bool ShouldHighlightFields() {
  std::string group_name =
      base::FieldTrialList::FindFullName(kFillOnAccountSelectFieldTrialName);
  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
          switches::kDisableFillOnAccountSelect) ||
      base::CommandLine::ForCurrentProcess()->HasSwitch(
          switches::kEnableFillOnAccountSelect)) {
    return true;
  }

  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
          switches::kEnableFillOnAccountSelectNoHighlighting)) {
    return false;
  }

  return group_name !=
         kFillOnAccountSelectFieldTrialEnabledWithNoHighlightGroup;
}

// Helper to search through |control_elements| for the specified input elements
// in |data|, and add results to |result|.
bool FindFormInputElements(
    const std::vector<blink::WebFormControlElement>& control_elements,
    const PasswordFormFillData& data,
    bool ambiguous_or_empty_names,
    FormInputElementMap* result) {
  return FindFormInputElement(control_elements, data.password_field,
                              ambiguous_or_empty_names, result) &&
         (!FillDataContainsFillableUsername(data) ||
          FindFormInputElement(control_elements, data.username_field,
                               ambiguous_or_empty_names, result));
}

// Helper to locate form elements identified by |data|.
void FindFormElements(content::RenderFrame* render_frame,
                      const PasswordFormFillData& data,
                      bool ambiguous_or_empty_names,
                      FormElementsList* results) {
  DCHECK(results);

  blink::WebDocument doc = render_frame->GetWebFrame()->document();
  if (!doc.isHTMLDocument())
    return;

  if (data.origin != form_util::GetCanonicalOriginForDocument(doc))
    return;

  blink::WebVector<blink::WebFormElement> forms;
  doc.forms(forms);

  for (size_t i = 0; i < forms.size(); ++i) {
    blink::WebFormElement fe = forms[i];

    // Action URL must match.
    if (data.action != form_util::GetCanonicalActionForForm(fe))
      continue;

    std::vector<blink::WebFormControlElement> control_elements =
        form_util::ExtractAutofillableElementsInForm(fe);
    FormInputElementMap cur_map;
    if (FindFormInputElements(control_elements, data, ambiguous_or_empty_names,
                              &cur_map))
      results->push_back(cur_map);
  }
  // If the element to be filled are not in a <form> element, the "action" and
  // origin should be the same.
  if (data.action != data.origin)
    return;

  std::vector<blink::WebFormControlElement> control_elements =
      form_util::GetUnownedAutofillableFormFieldElements(doc.all(), nullptr);
  FormInputElementMap unowned_elements_map;
  if (FindFormInputElements(control_elements, data, ambiguous_or_empty_names,
                            &unowned_elements_map))
    results->push_back(unowned_elements_map);
}

bool IsElementEditable(const blink::WebInputElement& element) {
  return element.isEnabled() && !element.isReadOnly();
}

bool DoUsernamesMatch(const base::string16& username1,
                      const base::string16& username2,
                      bool exact_match) {
  if (exact_match)
    return username1 == username2;
  return FieldIsSuggestionSubstringStartingOnTokenBoundary(username1, username2,
                                                           true);
}

// Returns |true| if the given element is editable. Otherwise, returns |false|.
bool IsElementAutocompletable(const blink::WebInputElement& element) {
  return IsElementEditable(element);
}

// Return true if either password_value or new_password_value is not empty and
// not default.
bool FormContainsNonDefaultPasswordValue(const PasswordForm& password_form) {
  return (!password_form.password_value.empty() &&
          !password_form.password_value_is_default) ||
      (!password_form.new_password_value.empty() &&
       !password_form.new_password_value_is_default);
}

// Log a message including the name, method and action of |form|.
void LogHTMLForm(SavePasswordProgressLogger* logger,
                 SavePasswordProgressLogger::StringID message_id,
                 const blink::WebFormElement& form) {
  logger->LogHTMLForm(message_id,
                      form.name().utf8(),
                      GURL(form.action().utf8()));
}


// Returns true if there are any suggestions to be derived from |fill_data|.
// Unless |show_all| is true, only considers suggestions with usernames having
// |current_username| as a prefix.
bool CanShowSuggestion(const PasswordFormFillData& fill_data,
                       const base::string16& current_username,
                       bool show_all) {
  base::string16 current_username_lower = base::i18n::ToLower(current_username);
  for (const auto& usernames : fill_data.other_possible_usernames) {
    for (size_t i = 0; i < usernames.second.size(); ++i) {
      if (show_all ||
          base::StartsWith(
              base::i18n::ToLower(base::string16(usernames.second[i])),
              current_username_lower, base::CompareCase::SENSITIVE)) {
        return true;
      }
    }
  }

  if (show_all ||
      base::StartsWith(base::i18n::ToLower(fill_data.username_field.value),
                       current_username_lower, base::CompareCase::SENSITIVE)) {
    return true;
  }

  for (const auto& login : fill_data.additional_logins) {
    if (show_all ||
        base::StartsWith(base::i18n::ToLower(login.first),
                         current_username_lower,
                         base::CompareCase::SENSITIVE)) {
      return true;
    }
  }

  return false;
}

// Returns true if there exists a credential suggestion whose username field is
// an exact match to the current username (not just a prefix).
bool HasExactMatchSuggestion(const PasswordFormFillData& fill_data,
                             const base::string16& current_username) {
  if (fill_data.username_field.value == current_username)
    return true;

  for (const auto& usernames : fill_data.other_possible_usernames) {
    for (const auto& username_string : usernames.second) {
      if (username_string == current_username)
        return true;
    }
  }

  for (const auto& login : fill_data.additional_logins) {
    if (login.first == current_username)
      return true;
  }

  return false;
}

// This function attempts to fill |username_element| and |password_element|
// with values from |fill_data|. The |password_element| will only have the
// suggestedValue set, and will be registered for copying that to the real
// value through |registration_callback|. If a match is found, return true and
// |nonscript_modified_values| will be modified with the autofilled credentials.
bool FillUserNameAndPassword(
    blink::WebInputElement* username_element,
    blink::WebInputElement* password_element,
    const PasswordFormFillData& fill_data,
    bool exact_username_match,
    bool set_selection,
    std::map<const blink::WebInputElement, blink::WebString>*
        nonscript_modified_values,
    base::Callback<void(blink::WebInputElement*)> registration_callback,
    RendererSavePasswordProgressLogger* logger) {
  if (logger)
    logger->LogMessage(Logger::STRING_FILL_USERNAME_AND_PASSWORD_METHOD);

  // Don't fill username if password can't be set.
  if (!IsElementAutocompletable(*password_element))
    return false;

  base::string16 current_username;
  if (!username_element->isNull()) {
    current_username = username_element->value();
  }

  // username and password will contain the match found if any.
  base::string16 username;
  base::string16 password;

  // Look for any suitable matches to current field text.
  if (DoUsernamesMatch(fill_data.username_field.value, current_username,
                       exact_username_match)) {
    username = fill_data.username_field.value;
    password = fill_data.password_field.value;
    if (logger)
      logger->LogMessage(Logger::STRING_USERNAMES_MATCH);
  } else {
    // Scan additional logins for a match.
    for (const auto& it : fill_data.additional_logins) {
      if (DoUsernamesMatch(it.first, current_username, exact_username_match)) {
        username = it.first;
        password = it.second.password;
        break;
      }
    }
    if (logger) {
      logger->LogBoolean(Logger::STRING_MATCH_IN_ADDITIONAL,
                         !(username.empty() && password.empty()));
    }

    // Check possible usernames.
    if (username.empty() && password.empty()) {
      for (const auto& it : fill_data.other_possible_usernames) {
        for (size_t i = 0; i < it.second.size(); ++i) {
          if (DoUsernamesMatch(
                  it.second[i], current_username, exact_username_match)) {
            username = it.second[i];
            password = it.first.password;
            break;
          }
        }
        if (!username.empty() && !password.empty())
          break;
      }
    }
  }
  if (password.empty())
    return false;

  // TODO(tkent): Check maxlength and pattern for both username and password
  // fields.

  // Input matches the username, fill in required values.
  if (!username_element->isNull() &&
      IsElementAutocompletable(*username_element)) {
    // TODO(crbug.com/507714): Why not setSuggestedValue?
    username_element->setValue(username, true);
    (*nonscript_modified_values)[*username_element] = username;
    username_element->setAutofilled(true);
    if (logger)
      logger->LogElementName(Logger::STRING_USERNAME_FILLED, *username_element);
    if (set_selection) {
      form_util::PreviewSuggestion(username, current_username,
                                   username_element);
    }
  } else if (current_username != username) {
    // If the username can't be filled and it doesn't match a saved password
    // as is, don't autofill a password.
    return false;
  }

  // Wait to fill in the password until a user gesture occurs. This is to make
  // sure that we do not fill in the DOM with a password until we believe the
  // user is intentionally interacting with the page.
  password_element->setSuggestedValue(password);
  (*nonscript_modified_values)[*password_element] = password;
  registration_callback.Run(password_element);

  password_element->setAutofilled(true);
  if (logger)
    logger->LogElementName(Logger::STRING_PASSWORD_FILLED, *password_element);
  return true;
}

// Attempts to fill |username_element| and |password_element| with the
// |fill_data|. Will use the data corresponding to the preferred username,
// unless the |username_element| already has a value set. In that case,
// attempts to fill the password matching the already filled username, if
// such a password exists. The |password_element| will have the
// |suggestedValue| set, and |suggestedValue| will be registered for copying to
// the real value through |registration_callback|. Returns true if the password
// is filled.
bool FillFormOnPasswordReceived(
    const PasswordFormFillData& fill_data,
    blink::WebInputElement username_element,
    blink::WebInputElement password_element,
    std::map<const blink::WebInputElement, blink::WebString>*
        nonscript_modified_values,
    base::Callback<void(blink::WebInputElement*)> registration_callback,
    RendererSavePasswordProgressLogger* logger) {
  // Do not fill if the password field is in a chain of iframes not having
  // identical origin.
  blink::WebFrame* cur_frame = password_element.document().frame();
  blink::WebString bottom_frame_origin =
      cur_frame->getSecurityOrigin().toString();

  DCHECK(cur_frame);

  while (cur_frame->parent()) {
    cur_frame = cur_frame->parent();
    if (!bottom_frame_origin.equals(cur_frame->getSecurityOrigin().toString()))
      return false;
  }

  // If we can't modify the password, don't try to set the username
  if (!IsElementAutocompletable(password_element))
    return false;

  bool form_contains_fillable_username_field =
      FillDataContainsFillableUsername(fill_data);
  bool ambiguous_or_empty_names =
      DoesFormContainAmbiguousOrEmptyNames(fill_data);
  base::string16 username_field_name;
  if (form_contains_fillable_username_field)
    username_field_name =
        FieldName(fill_data.username_field, ambiguous_or_empty_names);

  // If the form contains an autocompletable username field, try to set the
  // username to the preferred name, but only if:
  //   (a) The fill-on-account-select flag is not set, and
  //   (b) The username element isn't prefilled
  //
  // If (a) is false, then just mark the username element as autofilled if the
  // user is not in the "no highlighting" group and return so the fill step is
  // skipped.
  //
  // If there is no autocompletable username field, and (a) is false, then the
  // username element cannot be autofilled, but the user should still be able to
  // select to fill the password element, so the password element must be marked
  // as autofilled and the fill step should also be skipped if the user is not
  // in the "no highlighting" group.
  //
  // In all other cases, do nothing.
  bool form_has_fillable_username = !username_field_name.empty() &&
                                    IsElementAutocompletable(username_element);

  if (ShouldFillOnAccountSelect()) {
    if (!ShouldHighlightFields()) {
      return false;
    }

    if (form_has_fillable_username) {
      username_element.setAutofilled(true);
    } else if (username_element.isNull() ||
               HasExactMatchSuggestion(fill_data, username_element.value())) {
      password_element.setAutofilled(true);
    }
    return false;
  }

  if (form_has_fillable_username && username_element.value().isEmpty()) {
    // TODO(tkent): Check maxlength and pattern.
    username_element.setValue(fill_data.username_field.value, true);
  }

  // Fill if we have an exact match for the username. Note that this sets
  // username to autofilled.
  return FillUserNameAndPassword(
      &username_element, &password_element, fill_data,
      true /* exact_username_match */, false /* set_selection */,
      nonscript_modified_values, registration_callback, logger);
}

// Takes a |map| with pointers as keys and linked_ptr as values, and returns
// true if |key| is not NULL and  |map| contains a non-NULL entry for |key|.
// Makes sure not to create an entry as a side effect of using the operator [].
template <class Key, class Value>
bool ContainsNonNullEntryForNonNullKey(
    const std::map<Key*, linked_ptr<Value>>& map,
    Key* key) {
  if (!key)
    return false;
  auto it = map.find(key);
  return it != map.end() && it->second.get();
}

}  // namespace

////////////////////////////////////////////////////////////////////////////////
// PasswordAutofillAgent, public:

PasswordAutofillAgent::PasswordAutofillAgent(content::RenderFrame* render_frame)
    : content::RenderFrameObserver(render_frame),
      logging_state_active_(false),
      was_username_autofilled_(false),
      was_password_autofilled_(false) {
  Send(new AutofillHostMsg_PasswordAutofillAgentConstructed(routing_id()));
}

PasswordAutofillAgent::~PasswordAutofillAgent() {
}

PasswordAutofillAgent::PasswordValueGatekeeper::PasswordValueGatekeeper()
    : was_user_gesture_seen_(false) {
}

PasswordAutofillAgent::PasswordValueGatekeeper::~PasswordValueGatekeeper() {
}

void PasswordAutofillAgent::PasswordValueGatekeeper::RegisterElement(
    blink::WebInputElement* element) {
  if (was_user_gesture_seen_)
    ShowValue(element);
  else
    elements_.push_back(*element);
}

void PasswordAutofillAgent::PasswordValueGatekeeper::OnUserGesture() {
  was_user_gesture_seen_ = true;

  for (blink::WebInputElement& element : elements_)
    ShowValue(&element);

  elements_.clear();
}

void PasswordAutofillAgent::PasswordValueGatekeeper::Reset() {
  was_user_gesture_seen_ = false;
  elements_.clear();
}

void PasswordAutofillAgent::PasswordValueGatekeeper::ShowValue(
    blink::WebInputElement* element) {
  if (!element->isNull() && !element->suggestedValue().isEmpty())
    element->setValue(element->suggestedValue(), true);
}

bool PasswordAutofillAgent::TextFieldDidEndEditing(
    const blink::WebInputElement& element) {
  WebInputToPasswordInfoMap::const_iterator iter =
      web_input_to_password_info_.find(element);
  if (iter == web_input_to_password_info_.end())
    return false;

  const PasswordInfo& password_info = iter->second;
  // Don't let autofill overwrite an explicit change made by the user.
  if (password_info.password_was_edited_last)
    return false;

  const PasswordFormFillData& fill_data = password_info.fill_data;

  // If wait_for_username is false, we should have filled when the text changed.
  if (!fill_data.wait_for_username)
    return false;

  blink::WebInputElement password = password_info.password_field;
  if (!IsElementEditable(password))
    return false;

  blink::WebInputElement username = element;  // We need a non-const.

  // Do not set selection when ending an editing session, otherwise it can
  // mess with focus.
  FillUserNameAndPassword(&username, &password, fill_data, true, false,
                          &nonscript_modified_values_,
                          base::Bind(&PasswordValueGatekeeper::RegisterElement,
                                     base::Unretained(&gatekeeper_)),
                          nullptr);
  return true;
}

bool PasswordAutofillAgent::TextDidChangeInTextField(
    const blink::WebInputElement& element) {
  // TODO(vabr): Get a mutable argument instead. http://crbug.com/397083
  blink::WebInputElement mutable_element = element;  // We need a non-const.
  mutable_element.setAutofilled(false);

  WebInputToPasswordInfoMap::iterator iter =
      web_input_to_password_info_.find(element);
  if (iter != web_input_to_password_info_.end()) {
    iter->second.password_was_edited_last = false;
    // If wait_for_username is true we will fill when the username loses focus.
    if (iter->second.fill_data.wait_for_username)
      return false;
  }

  // Show the popup with the list of available usernames.
  return ShowSuggestions(element, false, false);
}

void PasswordAutofillAgent::UpdateStateForTextChange(
    const blink::WebInputElement& element) {
  // TODO(vabr): Get a mutable argument instead. http://crbug.com/397083
  blink::WebInputElement mutable_element = element;  // We need a non-const.

  if (element.isTextField())
    nonscript_modified_values_[element] = element.value();

  blink::WebFrame* const element_frame = element.document().frame();
  // The element's frame might have been detached in the meantime (see
  // http://crbug.com/585363, comments 5 and 6), in which case frame() will
  // return null. This was hardly caused by form submission (unless the user
  // is supernaturally quick), so it is OK to drop the ball here.
  if (!element_frame)
    return;
  DCHECK_EQ(element_frame, render_frame()->GetWebFrame());

  // Some login forms have event handlers that put a hash of the password into
  // a hidden field and then clear the password (http://crbug.com/28910,
  // http://crbug.com/391693). This method gets called before any of those
  // 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.
  std::unique_ptr<PasswordForm> password_form;
  if (element.form().isNull()) {
    password_form = CreatePasswordFormFromUnownedInputElements(
        *element_frame, &nonscript_modified_values_, &form_predictions_);
  } else {
    password_form = CreatePasswordFormFromWebForm(
        element.form(), &nonscript_modified_values_, &form_predictions_);
  }
  ProvisionallySavePassword(std::move(password_form), RESTRICTION_NONE);

  if (element.isPasswordField()) {
    PasswordToLoginMap::iterator iter = password_to_username_.find(element);
    if (iter != password_to_username_.end()) {
      web_input_to_password_info_[iter->second].password_was_edited_last = true;
      // Note that the suggested value of |mutable_element| was reset when its
      // value changed.
      mutable_element.setAutofilled(false);
    }
  }
}

bool PasswordAutofillAgent::FillSuggestion(
    const blink::WebFormControlElement& control_element,
    const blink::WebString& username,
    const blink::WebString& password) {
  // The element in context of the suggestion popup.
  const blink::WebInputElement* element = toWebInputElement(&control_element);
  if (!element)
    return false;

  blink::WebInputElement username_element;
  blink::WebInputElement password_element;
  PasswordInfo* password_info;

  if (!FindPasswordInfoForElement(*element, &username_element,
                                  &password_element, &password_info) ||
      (!username_element.isNull() &&
       !IsElementAutocompletable(username_element)) ||
      !IsElementAutocompletable(password_element)) {
    return false;
  }

  password_info->password_was_edited_last = false;
  if (element->isPasswordField()) {
    password_info->password_field_suggestion_was_accepted = true;
    password_info->password_field = password_element;
  } else if (!username_element.isNull()) {
    username_element.setValue(username, true);
    username_element.setAutofilled(true);
    nonscript_modified_values_[username_element] = username;
  }

  password_element.setValue(password, true);
  password_element.setAutofilled(true);
  nonscript_modified_values_[password_element] = password;

  blink::WebInputElement mutable_filled_element = *element;
  mutable_filled_element.setSelectionRange(element->value().length(),
                                           element->value().length());

  return true;
}

bool PasswordAutofillAgent::PreviewSuggestion(
    const blink::WebFormControlElement& control_element,
    const blink::WebString& username,
    const blink::WebString& password) {
  // The element in context of the suggestion popup.
  const blink::WebInputElement* element = toWebInputElement(&control_element);
  if (!element)
    return false;

  blink::WebInputElement username_element;
  blink::WebInputElement password_element;
  PasswordInfo* password_info;

  if (!FindPasswordInfoForElement(*element, &username_element,
                                  &password_element, &password_info) ||
      (!username_element.isNull() &&
       !IsElementAutocompletable(username_element)) ||
      !IsElementAutocompletable(password_element)) {
    return false;
  }

  if (!element->isPasswordField() && !username_element.isNull()) {
    if (username_query_prefix_.empty())
      username_query_prefix_ = username_element.value();

    was_username_autofilled_ = username_element.isAutofilled();
    username_element.setSuggestedValue(username);
    username_element.setAutofilled(true);
    form_util::PreviewSuggestion(username_element.suggestedValue(),
                                 username_query_prefix_, &username_element);
  }
  was_password_autofilled_ = password_element.isAutofilled();
  password_element.setSuggestedValue(password);
  password_element.setAutofilled(true);

  return true;
}

bool PasswordAutofillAgent::DidClearAutofillSelection(
    const blink::WebFormControlElement& control_element) {
  const blink::WebInputElement* element = toWebInputElement(&control_element);
  if (!element)
    return false;

  blink::WebInputElement username_element;
  blink::WebInputElement password_element;
  PasswordInfo* password_info;

  if (!FindPasswordInfoForElement(*element, &username_element,
                                  &password_element, &password_info))
    return false;

  ClearPreview(&username_element, &password_element);
  return true;
}

bool PasswordAutofillAgent::FindPasswordInfoForElement(
    const blink::WebInputElement& element,
    blink::WebInputElement* username_element,
    blink::WebInputElement* password_element,
    PasswordInfo** password_info) {
  DCHECK(username_element && password_element && password_info);
  username_element->reset();
  password_element->reset();
  if (!element.isPasswordField()) {
    *username_element = element;
  } else {
    WebInputToPasswordInfoMap::iterator iter =
        web_input_to_password_info_.find(element);
    if (iter != web_input_to_password_info_.end()) {
      // It's a password field without corresponding username field.
      *password_element = element;
      *password_info = &iter->second;
      return true;
    }
    PasswordToLoginMap::const_iterator password_iter =
        password_to_username_.find(element);
    if (password_iter == password_to_username_.end()) {
      if (web_input_to_password_info_.empty())
        return false;

      *password_element = element;
      // Now all PasswordInfo items refer to the same set of credentials for
      // fill, so it is ok to take any of them.
      *password_info = &web_input_to_password_info_.begin()->second;
      return true;
    }
    *username_element = password_iter->second;
    *password_element = element;
  }

  WebInputToPasswordInfoMap::iterator iter =
      web_input_to_password_info_.find(*username_element);

  if (iter == web_input_to_password_info_.end())
    return false;

  *password_info = &iter->second;
  if (password_element->isNull())
    *password_element = (*password_info)->password_field;

  return true;
}

bool PasswordAutofillAgent::ShowSuggestions(
    const blink::WebInputElement& element,
    bool show_all,
    bool generation_popup_showing) {
  blink::WebInputElement username_element;
  blink::WebInputElement password_element;
  PasswordInfo* password_info;
  if (!FindPasswordInfoForElement(element, &username_element, &password_element,
                                  &password_info))
    return false;

  // If autocomplete='off' is set on the form elements, no suggestion dialog
  // should be shown. However, return |true| to indicate that this is a known
  // password form and that the request to show suggestions has been handled (as
  // a no-op).
  if (!element.isTextField() || !IsElementAutocompletable(element) ||
      !IsElementAutocompletable(password_element))
    return true;

  if (element.nameForAutofill().isEmpty() &&
      !DoesFormContainAmbiguousOrEmptyNames(password_info->fill_data)) {
    return false;  // If the field has no name, then we won't have values.
  }

  // Don't attempt to autofill with values that are too large.
  if (element.value().length() > kMaximumTextSizeForAutocomplete)
    return false;

  // If the element is a password field, do not to show a popup if the user has
  // already accepted a password suggestion on another password field.
  if (element.isPasswordField() &&
      (password_info->password_field_suggestion_was_accepted &&
       element != password_info->password_field))
    return true;

  UMA_HISTOGRAM_BOOLEAN(
      "PasswordManager.AutocompletePopupSuppressedByGeneration",
      generation_popup_showing);

  if (generation_popup_showing)
    return false;

  // Chrome should never show more than one account for a password element since
  // this implies that the username element cannot be modified. Thus even if
  // |show_all| is true, check if the element in question is a password element
  // for the call to ShowSuggestionPopup.
  return ShowSuggestionPopup(*password_info, element,
                             show_all && !element.isPasswordField(),
                             element.isPasswordField());
}

bool PasswordAutofillAgent::OriginCanAccessPasswordManager(
    const blink::WebSecurityOrigin& origin) {
  return origin.canAccessPasswordManager();
}

void PasswordAutofillAgent::OnDynamicFormsSeen() {
  SendPasswordForms(false /* only_visible */);
}

void PasswordAutofillAgent::AJAXSucceeded() {
  OnSamePageNavigationCompleted();
}

void PasswordAutofillAgent::OnSamePageNavigationCompleted() {
  if (!ProvisionallySavedPasswordIsValid())
    return;

  // Prompt to save only if the form is now gone, either invisible or
  // removed from the DOM.
  blink::WebFrame* frame = render_frame()->GetWebFrame();
  if (form_util::IsFormVisible(frame, provisionally_saved_form_->action,
                               provisionally_saved_form_->origin,
                               provisionally_saved_form_->form_data) ||
      IsUnownedPasswordFormVisible(frame, provisionally_saved_form_->action,
                                   provisionally_saved_form_->origin,
                                   provisionally_saved_form_->form_data,
                                   form_predictions_)) {
    return;
  }

  Send(new AutofillHostMsg_InPageNavigation(routing_id(),
                                            *provisionally_saved_form_));
  provisionally_saved_form_.reset();
}

void PasswordAutofillAgent::FirstUserGestureObserved() {
  gatekeeper_.OnUserGesture();
}

void PasswordAutofillAgent::SendPasswordForms(bool only_visible) {
  std::unique_ptr<RendererSavePasswordProgressLogger> logger;
  if (logging_state_active_) {
    logger.reset(new RendererSavePasswordProgressLogger(this, routing_id()));
    logger->LogMessage(Logger::STRING_SEND_PASSWORD_FORMS_METHOD);
    logger->LogBoolean(Logger::STRING_ONLY_VISIBLE, only_visible);
  }

  blink::WebFrame* frame = render_frame()->GetWebFrame();
  // Make sure that this security origin is allowed to use password manager.
  blink::WebSecurityOrigin origin = frame->document().getSecurityOrigin();
  if (logger) {
    logger->LogURL(Logger::STRING_SECURITY_ORIGIN,
                   GURL(origin.toString().utf8()));
  }
  if (!OriginCanAccessPasswordManager(origin)) {
    if (logger) {
      logger->LogMessage(Logger::STRING_SECURITY_ORIGIN_FAILURE);
    }
    return;
  }

  // Checks whether the webpage is a redirect page or an empty page.
  if (form_util::IsWebpageEmpty(frame)) {
    if (logger) {
      logger->LogMessage(Logger::STRING_WEBPAGE_EMPTY);
    }
    return;
  }

  blink::WebVector<blink::WebFormElement> forms;
  frame->document().forms(forms);
  if (logger)
    logger->LogNumber(Logger::STRING_NUMBER_OF_ALL_FORMS, forms.size());

  std::vector<PasswordForm> password_forms;
  for (const blink::WebFormElement& form : forms) {
    if (only_visible) {
      bool is_form_visible = form_util::AreFormContentsVisible(form);
      if (logger) {
        LogHTMLForm(logger.get(), Logger::STRING_FORM_FOUND_ON_PAGE, form);
        logger->LogBoolean(Logger::STRING_FORM_IS_VISIBLE, is_form_visible);
      }

      // If requested, ignore non-rendered forms, e.g., those styled with
      // display:none.
      if (!is_form_visible)
        continue;
    }

    std::unique_ptr<PasswordForm> password_form(
        CreatePasswordFormFromWebForm(form, nullptr, &form_predictions_));
    if (password_form) {
      if (logger) {
        logger->LogPasswordForm(Logger::STRING_FORM_IS_PASSWORD,
                                *password_form);
      }
      password_forms.push_back(*password_form);
    }
  }

  // See if there are any unattached input elements that could be used for
  // password submission.
  bool add_unowned_inputs = true;
  if (only_visible) {
    std::vector<blink::WebFormControlElement> control_elements =
        form_util::GetUnownedAutofillableFormFieldElements(
            frame->document().all(), nullptr);
    add_unowned_inputs =
        form_util::IsSomeControlElementVisible(control_elements);
    if (logger) {
      logger->LogBoolean(Logger::STRING_UNOWNED_INPUTS_VISIBLE,
                         add_unowned_inputs);
    }
  }
  if (add_unowned_inputs) {
    std::unique_ptr<PasswordForm> password_form(
        CreatePasswordFormFromUnownedInputElements(*frame, nullptr,
                                                   &form_predictions_));
    if (password_form) {
      if (logger) {
        logger->LogPasswordForm(Logger::STRING_FORM_IS_PASSWORD,
                                *password_form);
      }
      password_forms.push_back(*password_form);
    }
  }

  if (password_forms.empty() && !only_visible) {
    // We need to send the PasswordFormsRendered message regardless of whether
    // there are any forms visible, as this is also the code path that triggers
    // showing the infobar.
    return;
  }

  if (only_visible) {
    blink::WebFrame* main_frame = render_frame()->GetWebFrame()->top();
    bool did_stop_loading = !main_frame || !main_frame->isLoading();
    Send(new AutofillHostMsg_PasswordFormsRendered(routing_id(), password_forms,
                                                   did_stop_loading));
  } else {
    Send(new AutofillHostMsg_PasswordFormsParsed(routing_id(), password_forms));
  }
}

bool PasswordAutofillAgent::OnMessageReceived(const IPC::Message& message) {
  bool handled = true;
  IPC_BEGIN_MESSAGE_MAP(PasswordAutofillAgent, message)
    IPC_MESSAGE_HANDLER(AutofillMsg_FillPasswordForm, OnFillPasswordForm)
    IPC_MESSAGE_HANDLER(AutofillMsg_SetLoggingState, OnSetLoggingState)
    IPC_MESSAGE_HANDLER(AutofillMsg_AutofillUsernameAndPasswordDataReceived,
                        OnAutofillUsernameAndPasswordDataReceived)
    IPC_MESSAGE_HANDLER(AutofillMsg_FindFocusedPasswordForm,
                        OnFindFocusedPasswordForm)
    IPC_MESSAGE_UNHANDLED(handled = false)
  IPC_END_MESSAGE_MAP()
  return handled;
}

void PasswordAutofillAgent::DidFinishDocumentLoad() {
  // The |frame| contents have been parsed, but not yet rendered.  Let the
  // PasswordManager know that forms are loaded, even though we can't yet tell
  // whether they're visible.
  SendPasswordForms(false);
}

void PasswordAutofillAgent::DidFinishLoad() {
  // The |frame| contents have been rendered.  Let the PasswordManager know
  // which of the loaded frames are actually visible to the user.  This also
  // triggers the "Save password?" infobar if the user just submitted a password
  // form.
  SendPasswordForms(true);
}

void PasswordAutofillAgent::FrameWillClose() {
  FrameClosing();
}

void PasswordAutofillAgent::DidCommitProvisionalLoad(
    bool is_new_navigation, bool is_same_page_navigation) {
  if (is_same_page_navigation) {
    OnSamePageNavigationCompleted();
  }
}

void PasswordAutofillAgent::FrameDetached() {
  // If a sub frame has been destroyed while the user was entering information
  // into a password form, try to save the data. See https://crbug.com/450806
  // for examples of sites that perform login using this technique.
  if (render_frame()->GetWebFrame()->parent() &&
      ProvisionallySavedPasswordIsValid()) {
    Send(new AutofillHostMsg_InPageNavigation(routing_id(),
                                              *provisionally_saved_form_));
  }
  FrameClosing();
}

void PasswordAutofillAgent::WillSendSubmitEvent(
    const blink::WebFormElement& form) {
  // Forms submitted via XHR are not seen by WillSubmitForm if the default
  // onsubmit handler is overridden. Such submission first gets detected in
  // DidStartProvisionalLoad, which no longer knows about the particular form,
  // and uses the candidate stored in |provisionally_saved_form_|.
  //
  // User-typed password will get stored to |provisionally_saved_form_| in
  // TextDidChangeInTextField. Autofilled or JavaScript-copied passwords need to
  // be saved here.
  //
  // Only non-empty passwords are saved here. Empty passwords were likely
  // cleared by some scripts (http://crbug.com/28910, http://crbug.com/391693).
  // Had the user cleared the password, |provisionally_saved_form_| would
  // already have been updated in TextDidChangeInTextField.
  std::unique_ptr<PasswordForm> password_form = CreatePasswordFormFromWebForm(
      form, &nonscript_modified_values_, &form_predictions_);
  ProvisionallySavePassword(std::move(password_form),
                            RESTRICTION_NON_EMPTY_PASSWORD);
}

void PasswordAutofillAgent::WillSubmitForm(const blink::WebFormElement& form) {
  std::unique_ptr<RendererSavePasswordProgressLogger> logger;
  if (logging_state_active_) {
    logger.reset(new RendererSavePasswordProgressLogger(this, routing_id()));
    logger->LogMessage(Logger::STRING_WILL_SUBMIT_FORM_METHOD);
    LogHTMLForm(logger.get(), Logger::STRING_HTML_FORM_FOR_SUBMIT, form);
  }

  std::unique_ptr<PasswordForm> submitted_form = CreatePasswordFormFromWebForm(
      form, &nonscript_modified_values_, &form_predictions_);

  // If there is a provisionally saved password, copy over the previous
  // password value so we get the user's typed password, not the value that
  // may have been transformed for submit.
  // TODO(gcasto): Do we need to have this action equality check? Is it trying
  // to prevent accidentally copying over passwords from a different form?
  if (submitted_form) {
    if (logger) {
      logger->LogPasswordForm(Logger::STRING_CREATED_PASSWORD_FORM,
                              *submitted_form);
    }
    if (provisionally_saved_form_ &&
        submitted_form->action == provisionally_saved_form_->action) {
      if (logger)
        logger->LogMessage(Logger::STRING_SUBMITTED_PASSWORD_REPLACED);
      submitted_form->password_value =
          provisionally_saved_form_->password_value;
      submitted_form->new_password_value =
          provisionally_saved_form_->new_password_value;
      submitted_form->username_value =
          provisionally_saved_form_->username_value;
    }

    // Some observers depend on sending this information now instead of when
    // the frame starts loading. If there are redirects that cause a new
    // RenderView to be instantiated (such as redirects to the WebStore)
    // we will never get to finish the load.
    Send(new AutofillHostMsg_PasswordFormSubmitted(routing_id(),
                                                   *submitted_form));
    provisionally_saved_form_.reset();
  } else if (logger) {
    logger->LogMessage(Logger::STRING_FORM_IS_NOT_PASSWORD);
  }
}

void PasswordAutofillAgent::DidStartProvisionalLoad() {
  std::unique_ptr<RendererSavePasswordProgressLogger> logger;
  if (logging_state_active_) {
    logger.reset(new RendererSavePasswordProgressLogger(this, routing_id()));
    logger->LogMessage(Logger::STRING_DID_START_PROVISIONAL_LOAD_METHOD);
  }

  const blink::WebLocalFrame* navigated_frame = render_frame()->GetWebFrame();
  if (navigated_frame->parent()) {
    if (logger)
      logger->LogMessage(Logger::STRING_FRAME_NOT_MAIN_FRAME);
    return;
  }

  // Bug fix for crbug.com/368690. isProcessingUserGesture() is false when
  // the user is performing actions outside the page (e.g. typed url,
  // history navigation). We don't want to trigger saving in these cases.
  content::DocumentState* document_state =
      content::DocumentState::FromDataSource(
          navigated_frame->provisionalDataSource());
  content::NavigationState* navigation_state =
      document_state->navigation_state();
  ui::PageTransition type = navigation_state->GetTransitionType();
  if (ui::PageTransitionIsWebTriggerable(type) &&
      ui::PageTransitionIsNewNavigation(type) &&
      !blink::WebUserGestureIndicator::isProcessingUserGesture()) {
    // If onsubmit has been called, try and save that form.
    if (provisionally_saved_form_) {
      if (logger) {
        logger->LogPasswordForm(
            Logger::STRING_PROVISIONALLY_SAVED_FORM_FOR_FRAME,
            *provisionally_saved_form_);
      }
      Send(new AutofillHostMsg_PasswordFormSubmitted(
          routing_id(), *provisionally_saved_form_));
      provisionally_saved_form_.reset();
    } else {
      ScopedVector<PasswordForm> possible_submitted_forms;
      // Loop through the forms on the page looking for one that has been
      // filled out. If one exists, try and save the credentials.
      blink::WebVector<blink::WebFormElement> forms;
      render_frame()->GetWebFrame()->document().forms(forms);

      bool password_forms_found = false;
      for (size_t i = 0; i < forms.size(); ++i) {
        blink::WebFormElement form_element = forms[i];
        if (logger) {
          LogHTMLForm(logger.get(), Logger::STRING_FORM_FOUND_ON_PAGE,
                      form_element);
        }
        possible_submitted_forms.push_back(CreatePasswordFormFromWebForm(
            form_element, &nonscript_modified_values_, &form_predictions_));
      }

      possible_submitted_forms.push_back(
          CreatePasswordFormFromUnownedInputElements(
              *render_frame()->GetWebFrame(),
              &nonscript_modified_values_,
              &form_predictions_));

      for (const PasswordForm* password_form : possible_submitted_forms) {
        if (password_form && !password_form->username_value.empty() &&
            FormContainsNonDefaultPasswordValue(*password_form)) {
          password_forms_found = true;
          if (logger) {
            logger->LogPasswordForm(Logger::STRING_PASSWORD_FORM_FOUND_ON_PAGE,
                                    *password_form);
          }
          Send(new AutofillHostMsg_PasswordFormSubmitted(routing_id(),
                                                         *password_form));
          break;
        }
      }

      if (!password_forms_found && logger)
        logger->LogMessage(Logger::STRING_PASSWORD_FORM_NOT_FOUND_ON_PAGE);
    }
  }

  // This is a new navigation, so require a new user gesture before filling in
  // passwords.
  gatekeeper_.Reset();
}

void PasswordAutofillAgent::OnFillPasswordForm(
    int key,
    const PasswordFormFillData& form_data) {
  std::unique_ptr<RendererSavePasswordProgressLogger> logger;
  if (logging_state_active_) {
    logger.reset(new RendererSavePasswordProgressLogger(this, routing_id()));
    logger->LogMessage(Logger::STRING_ON_FILL_PASSWORD_FORM_METHOD);
  }

  bool ambiguous_or_empty_names =
      DoesFormContainAmbiguousOrEmptyNames(form_data);
  FormElementsList forms;
  FindFormElements(render_frame(), form_data, ambiguous_or_empty_names, &forms);
  if (logger) {
    logger->LogBoolean(Logger::STRING_AMBIGUOUS_OR_EMPTY_NAMES,
                       ambiguous_or_empty_names);
    logger->LogNumber(Logger::STRING_NUMBER_OF_POTENTIAL_FORMS_TO_FILL,
                      forms.size());
    logger->LogBoolean(Logger::STRING_FORM_DATA_WAIT,
                       form_data.wait_for_username);
  }
  for (const auto& form : forms) {
    base::string16 username_field_name;
    base::string16 password_field_name =
        FieldName(form_data.password_field, ambiguous_or_empty_names);
    bool form_contains_fillable_username_field =
        FillDataContainsFillableUsername(form_data);
    if (form_contains_fillable_username_field) {
      username_field_name =
          FieldName(form_data.username_field, ambiguous_or_empty_names);
    }
    if (logger) {
      logger->LogBoolean(Logger::STRING_CONTAINS_FILLABLE_USERNAME_FIELD,
                         form_contains_fillable_username_field);
      logger->LogBoolean(Logger::STRING_USERNAME_FIELD_NAME_EMPTY,
                         username_field_name.empty());
      logger->LogBoolean(Logger::STRING_PASSWORD_FIELD_NAME_EMPTY,
                         password_field_name.empty());
    }

    // Attach autocomplete listener to enable selecting alternate logins.
    blink::WebInputElement username_element;
    blink::WebInputElement password_element;

    // Check whether the password form has a username input field.
    if (!username_field_name.empty()) {
      const auto it = form.find(username_field_name);
      DCHECK(it != form.end());
      username_element = it->second;
    }

    // No password field, bail out.
    if (password_field_name.empty())
      break;

    // Get pointer to password element. (We currently only support single
    // password forms).
    {
      const auto it = form.find(password_field_name);
      DCHECK(it != form.end());
      password_element = it->second;
    }

    blink::WebInputElement main_element =
        username_element.isNull() ? password_element : username_element;

    // We might have already filled this form if there are two <form> elements
    // with identical markup.
    if (web_input_to_password_info_.find(main_element) !=
        web_input_to_password_info_.end())
      continue;

    // If wait_for_username is true, we don't want to initially fill the form
    // until the user types in a valid username.
    if (!form_data.wait_for_username) {
      FillFormOnPasswordReceived(
          form_data, username_element, password_element,
          &nonscript_modified_values_,
          base::Bind(&PasswordValueGatekeeper::RegisterElement,
                     base::Unretained(&gatekeeper_)),
          logger.get());
    }

    PasswordInfo password_info;
    password_info.fill_data = form_data;
    password_info.key = key;
    password_info.password_field = password_element;
    web_input_to_password_info_[main_element] = password_info;
    if (!main_element.isPasswordField())
      password_to_username_[password_element] = username_element;
  }
}

void PasswordAutofillAgent::OnSetLoggingState(bool active) {
  logging_state_active_ = active;
}

void PasswordAutofillAgent::OnAutofillUsernameAndPasswordDataReceived(
    const FormsPredictionsMap& predictions) {
  form_predictions_.insert(predictions.begin(), predictions.end());
}

void PasswordAutofillAgent::OnFindFocusedPasswordForm() {
  std::unique_ptr<PasswordForm> password_form;

  blink::WebElement element = render_frame()->GetFocusedElement();
  if (!element.isNull() && element.hasHTMLTagName("input")) {
    blink::WebInputElement input = element.to<blink::WebInputElement>();
    if (input.isPasswordField() && !input.form().isNull()) {
      if (!input.form().isNull()) {
        password_form = CreatePasswordFormFromWebForm(
            input.form(), &nonscript_modified_values_, &form_predictions_);
      } else {
        password_form = CreatePasswordFormFromUnownedInputElements(
            *render_frame()->GetWebFrame(),
            &nonscript_modified_values_, &form_predictions_);
        // Only try to use this form if |input| is one of the password elements
        // for |password_form|.
        if (password_form->password_element != input.nameForAutofill() &&
            password_form->new_password_element != input.nameForAutofill())
          password_form.reset();
      }
    }
  }

  if (!password_form)
    password_form.reset(new PasswordForm());

  Send(new AutofillHostMsg_FocusedPasswordFormFound(
      routing_id(), *password_form));
}

////////////////////////////////////////////////////////////////////////////////
// PasswordAutofillAgent, private:

bool PasswordAutofillAgent::ShowSuggestionPopup(
    const PasswordInfo& password_info,
    const blink::WebInputElement& user_input,
    bool show_all,
    bool show_on_password_field) {
  DCHECK(!user_input.isNull());
  blink::WebFrame* frame = user_input.document().frame();
  if (!frame)
    return false;

  blink::WebView* webview = frame->view();
  if (!webview)
    return false;

  if (user_input.isPasswordField() && !user_input.isAutofilled() &&
      !user_input.value().isEmpty()) {
    Send(new AutofillHostMsg_HidePopup(routing_id()));
    return false;
  }

  FormData form;
  FormFieldData field;
  form_util::FindFormAndFieldForFormControlElement(user_input, &form, &field);

  int options = 0;
  if (show_all)
    options |= SHOW_ALL;
  if (show_on_password_field)
    options |= IS_PASSWORD_FIELD;

  base::string16 username_string(
      user_input.isPasswordField()
          ? base::string16()
          : static_cast<base::string16>(user_input.value()));

  Send(new AutofillHostMsg_ShowPasswordSuggestions(
      routing_id(), password_info.key, field.text_direction, username_string,
      options,
      render_frame()->GetRenderView()->ElementBoundsInWindow(user_input)));
  username_query_prefix_ = username_string;
  return CanShowSuggestion(password_info.fill_data, username_string, show_all);
}

void PasswordAutofillAgent::FrameClosing() {
  for (auto const& iter : web_input_to_password_info_) {
    password_to_username_.erase(iter.second.password_field);
  }
  web_input_to_password_info_.clear();
  provisionally_saved_form_.reset();
  nonscript_modified_values_.clear();
}

void PasswordAutofillAgent::ClearPreview(
    blink::WebInputElement* username,
    blink::WebInputElement* password) {
  if (!username->isNull() && !username->suggestedValue().isEmpty()) {
    username->setSuggestedValue(blink::WebString());
    username->setAutofilled(was_username_autofilled_);
    username->setSelectionRange(username_query_prefix_.length(),
                                username->value().length());
  }
  if (!password->suggestedValue().isEmpty()) {
      password->setSuggestedValue(blink::WebString());
      password->setAutofilled(was_password_autofilled_);
  }
}

void PasswordAutofillAgent::ProvisionallySavePassword(
    std::unique_ptr<PasswordForm> password_form,
    ProvisionallySaveRestriction restriction) {
  if (!password_form || (restriction == RESTRICTION_NON_EMPTY_PASSWORD &&
                         password_form->password_value.empty() &&
                         password_form->new_password_value.empty())) {
    return;
  }
  provisionally_saved_form_ = std::move(password_form);
}

bool PasswordAutofillAgent::ProvisionallySavedPasswordIsValid() {
  return provisionally_saved_form_ &&
         !provisionally_saved_form_->username_value.empty() &&
         !(provisionally_saved_form_->password_value.empty() &&
         provisionally_saved_form_->new_password_value.empty());
}

}  // namespace autofill