components/omnibox/browser/autocomplete_controller.cc

// Copyright (c) 2012 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/omnibox/browser/autocomplete_controller.h"

#include <inttypes.h>

#include <cstddef>
#include <memory>
#include <numeric>
#include <set>
#include <string>
#include <utility>

#include "base/bind.h"
#include "base/feature_list.h"
#include "base/format_macros.h"
#include "base/logging.h"
#include "base/metrics/histogram.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/stringprintf.h"
#include "base/strings/utf_string_conversions.h"
#include "base/time/time.h"
#include "base/trace_event/memory_dump_manager.h"
#include "base/trace_event/memory_usage_estimator.h"
#include "base/trace_event/trace_event.h"
#include "build/build_config.h"
#include "components/omnibox/browser/autocomplete_controller_delegate.h"
#include "components/omnibox/browser/bookmark_provider.h"
#include "components/omnibox/browser/builtin_provider.h"
#include "components/omnibox/browser/clipboard_provider.h"
#include "components/omnibox/browser/document_provider.h"
#include "components/omnibox/browser/history_quick_provider.h"
#include "components/omnibox/browser/history_url_provider.h"
#include "components/omnibox/browser/keyword_provider.h"
#include "components/omnibox/browser/search_provider.h"
#include "components/omnibox/browser/shortcuts_provider.h"
#include "components/omnibox/browser/zero_suggest_provider.h"
#include "components/omnibox/common/omnibox_features.h"
#include "components/open_from_clipboard/clipboard_recent_content.h"
#include "components/search_engines/template_url.h"
#include "components/search_engines/template_url_service.h"
#include "components/strings/grit/components_strings.h"
#include "ui/base/device_form_factor.h"
#include "ui/base/l10n/l10n_util.h"

#if !defined(OS_IOS)
#include "components/open_from_clipboard/clipboard_recent_content_generic.h"
#endif

namespace {

// Converts the given match to a type (and possibly subtype) based on the AQS
// specification. For more details, see
// http://goto.google.com/binary-clients-logging.
void AutocompleteMatchToAssistedQuery(
    const AutocompleteMatch::Type& match,
    const AutocompleteProvider* provider,
    size_t* type,
    size_t* subtype) {
  // This type indicates a native chrome suggestion.
  *type = 69;
  // Default value, indicating no subtype.
  *subtype = base::string16::npos;

  // If provider is TYPE_ZERO_SUGGEST or TYPE_ON_DEVICE_HEAD, set the subtype
  // accordingly. Type will be set in the switch statement below where we'll
  // enter one of SEARCH_SUGGEST or NAVSUGGEST.
  if (provider) {
    if (provider->type() == AutocompleteProvider::TYPE_ZERO_SUGGEST &&
        (match != AutocompleteMatchType::SEARCH_SUGGEST_PERSONALIZED)) {
      DCHECK((match == AutocompleteMatchType::SEARCH_SUGGEST) ||
             (match == AutocompleteMatchType::NAVSUGGEST));
      // We abuse this subtype and use it to for zero-suggest suggestions that
      // aren't personalized by the server. That is, it indicates either
      // client-side most-likely URL suggestions or server-side suggestions
      // that depend only on the URL as context.
      *subtype = 66;
    } else if (provider->type() == AutocompleteProvider::TYPE_ON_DEVICE_HEAD) {
      DCHECK(match == AutocompleteMatchType::SEARCH_SUGGEST);
      // This subtype indicates a match from an on-device head provider.
      *subtype = 271;
    }
  }

  switch (match) {
    case AutocompleteMatchType::SEARCH_SUGGEST: {
      // Do not set subtype here; subtype may have been set above.
      *type = 0;
      return;
    }
    case AutocompleteMatchType::SEARCH_SUGGEST_ENTITY: {
      *type = 46;
      return;
    }
    case AutocompleteMatchType::SEARCH_SUGGEST_TAIL: {
      *type = 33;
      return;
    }
    case AutocompleteMatchType::SEARCH_SUGGEST_PERSONALIZED: {
      *type = 35;
      *subtype = 39;
      return;
    }
    case AutocompleteMatchType::SEARCH_SUGGEST_PROFILE: {
      *type = 44;
      return;
    }
    case AutocompleteMatchType::NAVSUGGEST: {
      // Do not set subtype here; subtype may have been set above.
      *type = 5;
      return;
    }
    case AutocompleteMatchType::SEARCH_WHAT_YOU_TYPED: {
      *subtype = 57;
      return;
    }
    case AutocompleteMatchType::URL_WHAT_YOU_TYPED: {
      *subtype = 58;
      return;
    }
    case AutocompleteMatchType::SEARCH_HISTORY: {
      *subtype = 59;
      return;
    }
    case AutocompleteMatchType::HISTORY_URL: {
      *subtype = 60;
      return;
    }
    case AutocompleteMatchType::HISTORY_TITLE: {
      *subtype = 61;
      return;
    }
    case AutocompleteMatchType::HISTORY_BODY: {
      *subtype = 62;
      return;
    }
    case AutocompleteMatchType::HISTORY_KEYWORD: {
      *subtype = 63;
      return;
    }
    case AutocompleteMatchType::BOOKMARK_TITLE: {
      *subtype = 65;
      return;
    }
    case AutocompleteMatchType::NAVSUGGEST_PERSONALIZED: {
      *type = 5;
      *subtype = 39;
      return;
    }
    case AutocompleteMatchType::CALCULATOR: {
      *type = 6;
      return;
    }
    case AutocompleteMatchType::CLIPBOARD_URL: {
      *subtype = 177;
      return;
    }
    case AutocompleteMatchType::CLIPBOARD_TEXT: {
      *subtype = 176;
      return;
    }
    case AutocompleteMatchType::CLIPBOARD_IMAGE: {
      *subtype = 327;
      return;
    }
    default: {
      // This value indicates a native chrome suggestion with no named subtype
      // (yet).
      *subtype = 64;
    }
  }
}

// Appends available autocompletion of the given type, subtype, and number to
// the existing available autocompletions string, encoding according to the
// spec.
void AppendAvailableAutocompletion(size_t type,
                                   size_t subtype,
                                   int count,
                                   std::string* autocompletions) {
  if (!autocompletions->empty())
    autocompletions->append("j");
  base::StringAppendF(autocompletions, "%" PRIuS, type);
  // Subtype is optional - base::string16::npos indicates no subtype.
  if (subtype != base::string16::npos)
    base::StringAppendF(autocompletions, "i%" PRIuS, subtype);
  if (count > 1)
    base::StringAppendF(autocompletions, "l%d", count);
}

// Returns whether the autocompletion is trivial enough that we consider it
// an autocompletion for which the omnibox autocompletion code did not add
// any value.
bool IsTrivialAutocompletion(const AutocompleteMatch& match) {
  return match.type == AutocompleteMatchType::SEARCH_WHAT_YOU_TYPED ||
      match.type == AutocompleteMatchType::URL_WHAT_YOU_TYPED ||
      match.type == AutocompleteMatchType::SEARCH_OTHER_ENGINE;
}

// Whether this autocomplete match type supports custom descriptions.
bool AutocompleteMatchHasCustomDescription(const AutocompleteMatch& match) {
  if (ui::GetDeviceFormFactor() == ui::DEVICE_FORM_FACTOR_DESKTOP &&
      match.type == AutocompleteMatchType::CALCULATOR) {
    return true;
  }
  return match.type == AutocompleteMatchType::SEARCH_SUGGEST_ENTITY ||
         match.type == AutocompleteMatchType::SEARCH_SUGGEST_PROFILE;
}

}  // namespace

AutocompleteController::AutocompleteController(
    std::unique_ptr<AutocompleteProviderClient> provider_client,
    AutocompleteControllerDelegate* delegate,
    int provider_types)
    : delegate_(delegate),
      provider_client_(std::move(provider_client)),
      document_provider_(nullptr),
      history_url_provider_(nullptr),
      keyword_provider_(nullptr),
      search_provider_(nullptr),
      zero_suggest_provider_(nullptr),
      stop_timer_duration_(OmniboxFieldTrial::StopTimerFieldTrialDuration()),
      done_(true),
      in_start_(false),
      first_query_(true),
      search_service_worker_signal_sent_(false),
      template_url_service_(provider_client_->GetTemplateURLService()) {
  provider_types &= ~OmniboxFieldTrial::GetDisabledProviderTypes();
  if (provider_types & AutocompleteProvider::TYPE_BOOKMARK)
    providers_.push_back(new BookmarkProvider(provider_client_.get()));
  if (provider_types & AutocompleteProvider::TYPE_BUILTIN)
    providers_.push_back(new BuiltinProvider(provider_client_.get()));
  if (provider_types & AutocompleteProvider::TYPE_HISTORY_QUICK)
    providers_.push_back(new HistoryQuickProvider(provider_client_.get()));
  if (provider_types & AutocompleteProvider::TYPE_KEYWORD) {
    keyword_provider_ = new KeywordProvider(provider_client_.get(), this);
    providers_.push_back(keyword_provider_);
  }
  if (provider_types & AutocompleteProvider::TYPE_SEARCH) {
    search_provider_ = new SearchProvider(provider_client_.get(), this);
    providers_.push_back(search_provider_);
  }
  // It's important that the HistoryURLProvider gets added after SearchProvider:
  // AutocompleteController::Start() calls each providers' Start() function
  // synchronously in the order they're in in providers_.
  // - SearchProvider::Start() synchronously queries the history database's
  //   keyword_search_terms and url table.
  // - HistoryUrlProvider::Start schedules a background task that also accesses
  //   the history database.
  // If both db accesses happen concurrently, TSan complains.
  // So put HistoryURLProvider later to make sure that SearchProvider is done
  // doing its thing by the time the HistoryURLProvider task runs.
  // (And hope that it completes before AutocompleteController::Start() is
  // called the next time.)
  // ZeroSuggestProvider and ClipboardURLProvider take a reference to
  // HistoryURLProvider. If we're going to need either, we should initialize
  // history_url_provider_.
  if (provider_types & (AutocompleteProvider::TYPE_HISTORY_URL |
                        AutocompleteProvider::TYPE_ZERO_SUGGEST |
                        AutocompleteProvider::TYPE_CLIPBOARD)) {
    history_url_provider_ =
        new HistoryURLProvider(provider_client_.get(), this);
    if (provider_types & AutocompleteProvider::TYPE_HISTORY_URL)
      providers_.push_back(history_url_provider_);
  }
  if (provider_types & AutocompleteProvider::TYPE_SHORTCUTS)
    providers_.push_back(new ShortcutsProvider(provider_client_.get()));
  if (provider_types & AutocompleteProvider::TYPE_ZERO_SUGGEST) {
    zero_suggest_provider_ = ZeroSuggestProvider::Create(
        provider_client_.get(), history_url_provider_, this);
    if (zero_suggest_provider_)
      providers_.push_back(zero_suggest_provider_);
  }
  if (provider_types & AutocompleteProvider::TYPE_DOCUMENT) {
    document_provider_ = DocumentProvider::Create(provider_client_.get(), this);
    providers_.push_back(document_provider_);
  }
  if (provider_types & AutocompleteProvider::TYPE_CLIPBOARD) {
#if !defined(OS_IOS)
    // On iOS, a global ClipboardRecentContent should've been created by now
    // (if enabled).  If none has been created (e.g., we're on a different
    // platform), use the generic implementation, which AutocompleteController
    // will own.  Don't try to create a generic implementation on iOS because
    // iOS doesn't want/need to link in the implementation and the libraries
    // that would come with it.
    if (!ClipboardRecentContent::GetInstance()) {
      ClipboardRecentContent::SetInstance(
          std::make_unique<ClipboardRecentContentGeneric>());
    }
#endif
    // ClipboardRecentContent can be null in iOS tests.  For non-iOS, we
    // create a ClipboardRecentContent as above (for both Chrome and tests).
    if (ClipboardRecentContent::GetInstance()) {
      providers_.push_back(new ClipboardProvider(
          provider_client_.get(), this, history_url_provider_,
          ClipboardRecentContent::GetInstance()));
    }
  }

  base::trace_event::MemoryDumpManager::GetInstance()->RegisterDumpProvider(
      this, "AutocompleteController", base::ThreadTaskRunnerHandle::Get());
}

AutocompleteController::~AutocompleteController() {
  base::trace_event::MemoryDumpManager::GetInstance()->UnregisterDumpProvider(
      this);

  // The providers may have tasks outstanding that hold refs to them.  We need
  // to ensure they won't call us back if they outlive us.  (Practically,
  // calling Stop() should also cancel those tasks and make it so that we hold
  // the only refs.)  We also don't want to bother notifying anyone of our
  // result changes here, because the notification observer is in the midst of
  // shutdown too, so we don't ask Stop() to clear |result_| (and notify).
  result_.Reset();  // Not really necessary.
  Stop(false);
}

void AutocompleteController::Start(const AutocompleteInput& input) {
  TRACE_EVENT1("omnibox", "AutocompleteController::Start",
               "text", base::UTF16ToUTF8(input.text()));
  const base::string16 old_input_text(input_.text());
  const bool old_allow_exact_keyword_match = input_.allow_exact_keyword_match();
  const bool old_want_asynchronous_matches = input_.want_asynchronous_matches();
  const bool old_from_omnibox_focus = input_.from_omnibox_focus();
  input_ = input;

  // See if we can avoid rerunning autocomplete when the query hasn't changed
  // much.  When the user presses or releases the ctrl key, the desired_tld
  // changes, and when the user finishes an IME composition, inline autocomplete
  // may no longer be prevented.  In both these cases the text itself hasn't
  // changed since the last query, and some providers can do much less work (and
  // get matches back more quickly).  Taking advantage of this reduces flicker.
  //
  // NOTE: This comes after constructing |input_| above since that construction
  // can change the text string (e.g. by stripping off a leading '?').
  const bool minimal_changes =
      (input_.text() == old_input_text) &&
      (input_.allow_exact_keyword_match() == old_allow_exact_keyword_match) &&
      (input_.want_asynchronous_matches() == old_want_asynchronous_matches) &&
      (input.from_omnibox_focus() == old_from_omnibox_focus);

  expire_timer_.Stop();
  stop_timer_.Stop();

  // Start the new query.
  in_start_ = true;
  base::TimeTicks start_time = base::TimeTicks::Now();
  for (auto i(providers_.begin()); i != providers_.end(); ++i) {
    // TODO(mpearson): Remove timing code once bug 178705 is resolved.
    base::TimeTicks provider_start_time = base::TimeTicks::Now();
    (*i)->Start(input_, minimal_changes);
    if (!input.want_asynchronous_matches())
      DCHECK((*i)->done());
    base::TimeTicks provider_end_time = base::TimeTicks::Now();
    std::string name = std::string("Omnibox.ProviderTime2.") + (*i)->GetName();
    base::HistogramBase* counter = base::Histogram::FactoryGet(
        name, 1, 5000, 20, base::Histogram::kUmaTargetedHistogramFlag);
    counter->Add(static_cast<int>(
        (provider_end_time - provider_start_time).InMilliseconds()));
  }
  if (input.want_asynchronous_matches() && (input.text().length() < 6)) {
    base::TimeTicks end_time = base::TimeTicks::Now();
    std::string name =
        "Omnibox.QueryTime2." + base::NumberToString(input.text().length());
    base::HistogramBase* counter = base::Histogram::FactoryGet(
        name, 1, 1000, 50, base::Histogram::kUmaTargetedHistogramFlag);
    counter->Add(static_cast<int>((end_time - start_time).InMilliseconds()));
  }
  in_start_ = false;
  CheckIfDone();
  // The second true forces saying the default match has changed.
  // This triggers the edit model to update things such as the inline
  // autocomplete state.  In particular, if the user has typed a key
  // since the last notification, and we're now re-running
  // autocomplete, then we need to update the inline autocompletion
  // even if the current match is for the same URL as the last run's
  // default match.  Likewise, the controller doesn't know what's
  // happened in the edit since the last time it ran autocomplete.
  // The user might have selected all the text and hit delete, then
  // typed a new character.  The selection and delete won't send any
  // signals to the controller so it doesn't realize that anything was
  // cleared or changed.  Even if the default match hasn't changed, we
  // need the edit model to update the display.
  UpdateResult(false, true);

  // Omnibox has dependencies that may be lazily initialized. This metric will
  // help tracking regression on the first use.
  if (first_query_) {
    base::TimeTicks end_time = base::TimeTicks::Now();
    base::HistogramBase* counter =
        base::Histogram::FactoryGet("Omnibox.WarmupTime", 1, 1000, 50,
                                    base::Histogram::kUmaTargetedHistogramFlag);
    counter->Add(static_cast<int>((end_time - start_time).InMilliseconds()));
    first_query_ = false;
  }

  // If the input looks like a query, send a signal predicting that the user is
  // going to issue a search (either to the default search engine or to a
  // keyword search engine, as indicated by the destination_url). This allows
  // any associated service worker to start up early and reduce the latency of a
  // resulting search. However, to avoid a potentially expensive operation, we
  // only do this once per session. Additionally, a default match is expected to
  // be available at this point but we check anyway to guard against an invalid
  // dereference.
  if (base::FeatureList::IsEnabled(
          omnibox::kSpeculativeServiceWorkerStartOnQueryInput) &&
      (input.type() == metrics::OmniboxInputType::QUERY) &&
      !search_service_worker_signal_sent_ &&
      (result_.default_match() != result_.end())) {
    search_service_worker_signal_sent_ = true;
    provider_client_->StartServiceWorker(
        result_.default_match()->destination_url);
  }

  if (!done_) {
    StartExpireTimer();
    StartStopTimer();
  }
}

void AutocompleteController::Stop(bool clear_result) {
  StopHelper(clear_result, false);
}

void AutocompleteController::DeleteMatch(const AutocompleteMatch& match) {
  DCHECK(match.SupportsDeletion());

  // Delete duplicate matches attached to the main match first.
  for (auto it(match.duplicate_matches.begin());
       it != match.duplicate_matches.end(); ++it) {
    if (it->deletable)
      it->provider->DeleteMatch(*it);
  }

  if (match.deletable)
    match.provider->DeleteMatch(match);

  OnProviderUpdate(true);

  // If we're not done, we might attempt to redisplay the deleted match. Make
  // sure we aren't displaying it by removing any old entries.
  ExpireCopiedEntries();
}

void AutocompleteController::ExpireCopiedEntries() {
  // The first true makes UpdateResult() clear out the results and
  // regenerate them, thus ensuring that no results from the previous
  // result set remain.
  UpdateResult(true, false);
}

void AutocompleteController::OnProviderUpdate(bool updated_matches) {
  CheckIfDone();
  // Multiple providers may provide synchronous results, so we only update the
  // results if we're not in Start().
  if (!in_start_ && (updated_matches || done_))
    UpdateResult(false, false);
}

void AutocompleteController::AddProvidersInfo(
    ProvidersInfo* provider_info) const {
  provider_info->clear();
  for (auto i(providers_.begin()); i != providers_.end(); ++i) {
    // Add per-provider info, if any.
    (*i)->AddProviderInfo(provider_info);

    // This is also a good place to put code to add info that you want to
    // add for every provider.
  }
}

void AutocompleteController::ResetSession() {
  search_service_worker_signal_sent_ = false;

  for (Providers::const_iterator i(providers_.begin()); i != providers_.end();
       ++i)
    (*i)->ResetSession();
}

void AutocompleteController::UpdateMatchDestinationURLWithQueryFormulationTime(
    base::TimeDelta query_formulation_time,
    AutocompleteMatch* match) const {
  if (!match->search_terms_args ||
      match->search_terms_args->assisted_query_stats.empty())
    return;

  // Append the query formulation time (time from when the user first typed a
  // character into the omnibox to when the user selected a query) and whether
  // a field trial has triggered to the AQS parameter.
  TemplateURLRef::SearchTermsArgs search_terms_args(*match->search_terms_args);
  search_terms_args.assisted_query_stats += base::StringPrintf(
      ".%" PRId64 "j%dj%d",
      query_formulation_time.InMilliseconds(),
      (search_provider_ &&
       search_provider_->field_trial_triggered_in_session()) ||
      (zero_suggest_provider_ &&
       zero_suggest_provider_->field_trial_triggered_in_session()),
      input_.current_page_classification());
  UpdateMatchDestinationURL(search_terms_args, match);
}

void AutocompleteController::UpdateMatchDestinationURL(
    const TemplateURLRef::SearchTermsArgs& search_terms_args,
    AutocompleteMatch* match) const {
  const TemplateURL* template_url = match->GetTemplateURL(
      template_url_service_, false);
  if (!template_url)
    return;

  match->destination_url = GURL(template_url->url_ref().ReplaceSearchTerms(
      search_terms_args, template_url_service_->search_terms_data()));
}

void AutocompleteController::InlineTailPrefixes() {
  result_.InlineTailPrefixes();
}

void AutocompleteController::UpdateResult(
    bool regenerate_result,
    bool force_notify_default_match_changed) {
  TRACE_EVENT0("omnibox", "AutocompleteController::UpdateResult");
  const bool last_default_was_valid = result_.default_match() != result_.end();
  // The following three variables are only set and used if
  // |last_default_was_valid|.
  base::string16 last_default_fill_into_edit, last_default_keyword,
      last_default_associated_keyword;
  if (last_default_was_valid) {
    last_default_fill_into_edit = result_.default_match()->fill_into_edit;
    last_default_keyword = result_.default_match()->keyword;
    if (result_.default_match()->associated_keyword) {
      last_default_associated_keyword =
          result_.default_match()->associated_keyword->keyword;
    }
  }

  if (regenerate_result)
    result_.Reset();

  AutocompleteResult last_result;
  last_result.Swap(&result_);

  for (Providers::const_iterator i(providers_.begin());
       i != providers_.end(); ++i)
    result_.AppendMatches(input_, (*i)->matches());

  if (OmniboxFieldTrial::IsPedalSuggestionsEnabled())
    result_.AppendDedicatedPedalMatches(provider_client_.get(), input_);

  // Sort the matches and trim to a small number of "best" matches.
  result_.SortAndCull(input_, template_url_service_);

  if (OmniboxFieldTrial::IsTabSwitchSuggestionsEnabled())
    result_.ConvertOpenTabMatches(provider_client_.get(), &input_);

  // Need to validate before invoking CopyOldMatches as the old matches are not
  // valid against the current input.
#if DCHECK_IS_ON()
  result_.Validate();
#endif  // DCHECK_IS_ON()

  if (!done_) {
    // This conditional needs to match the conditional in Start that invokes
    // StartExpireTimer.
    result_.CopyOldMatches(input_, &last_result, template_url_service_);
  }

  UpdateKeywordDescriptions(&result_);
  UpdateAssociatedKeywords(&result_);
  UpdateAssistedQueryStats(&result_);
  if (search_provider_)
    search_provider_->RegisterDisplayedAnswers(result_);

  const bool default_is_valid = result_.default_match() != result_.end();
  base::string16 default_associated_keyword;
  if (default_is_valid &&
      result_.default_match()->associated_keyword) {
    default_associated_keyword =
        result_.default_match()->associated_keyword->keyword;
  }
  // We've gotten async results. Send notification that the default match
  // updated if fill_into_edit, associated_keyword, or keyword differ.  (The
  // second can change if we've just started Chrome and the keyword database
  // finishes loading while processing this request.  The third can change
  // if we swapped from interpreting the input as a search--which gets
  // labeled with the default search provider's keyword--to a URL.)
  // We don't check the URL as that may change for the default match
  // even though the fill into edit hasn't changed (see SearchProvider
  // for one case of this).
  const bool notify_default_match =
      (last_default_was_valid != default_is_valid) ||
      (last_default_was_valid &&
       ((result_.default_match()->fill_into_edit !=
          last_default_fill_into_edit) ||
        (default_associated_keyword != last_default_associated_keyword) ||
        (result_.default_match()->keyword != last_default_keyword)));
  if (notify_default_match)
    last_time_default_match_changed_ = base::TimeTicks::Now();

  NotifyChanged(force_notify_default_match_changed || notify_default_match);
}

void AutocompleteController::UpdateAssociatedKeywords(
    AutocompleteResult* result) {
  if (!keyword_provider_)
    return;

  // Determine if the user's input is an exact keyword match.
  base::string16 exact_keyword =
      keyword_provider_->GetKeywordForText(input_.text());

  std::set<base::string16> keywords;
  for (auto match(result->begin()); match != result->end(); ++match) {
    base::string16 keyword(
        match->GetSubstitutingExplicitlyInvokedKeyword(template_url_service_));
    if (!keyword.empty()) {
      keywords.insert(keyword);
      continue;
    }

    // When the user has typed an exact keyword, we want tab-to-search on the
    // default match to select that keyword, even if the match
    // inline-autocompletes to a different keyword.  (This prevents inline
    // autocompletions from blocking a user's attempts to use an explicitly-set
    // keyword of their own creation.)  So use |exact_keyword| if it's
    // available.
    if (!exact_keyword.empty() && !keywords.count(exact_keyword)) {
      keywords.insert(exact_keyword);
      match->associated_keyword.reset(new AutocompleteMatch(
          keyword_provider_->CreateVerbatimMatch(exact_keyword,
                                                 exact_keyword, input_)));
      continue;
    }

    // Otherwise, set a match's associated keyword based on the match's
    // fill_into_edit, which should take inline autocompletions into account.
    keyword = keyword_provider_->GetKeywordForText(match->fill_into_edit);

    // Only add the keyword if the match does not have a duplicate keyword with
    // a more relevant match.
    if (!keyword.empty() && !keywords.count(keyword)) {
      keywords.insert(keyword);
      match->associated_keyword.reset(new AutocompleteMatch(
          keyword_provider_->CreateVerbatimMatch(match->fill_into_edit,
                                                 keyword, input_)));
    } else {
      match->associated_keyword.reset();
    }
  }
}

void AutocompleteController::UpdateKeywordDescriptions(
    AutocompleteResult* result) {
  bool show_suffix_on_all_search_suggestions = base::FeatureList::IsEnabled(
      omnibox::kUIExperimentShowSuffixOnAllSearchSuggestions);

  base::string16 last_keyword;
  for (auto i(result->begin()); i != result->end(); ++i) {
    if (AutocompleteMatch::IsSearchType(i->type)) {
      if (AutocompleteMatchHasCustomDescription(*i))
        continue;
      i->description.clear();
      i->description_class.clear();
      DCHECK(!i->keyword.empty());
      if (show_suffix_on_all_search_suggestions ||
          (i->keyword != last_keyword &&
           !ShouldCurbKeywordDescriptions(i->keyword))) {
        const TemplateURL* template_url =
            i->GetTemplateURL(template_url_service_, false);
        if (template_url) {
          // For extension keywords, just make the description the extension
          // name -- don't assume that the normal search keyword description is
          // applicable.
          i->description = template_url->AdjustedShortNameForLocaleDirection();
          if (template_url->type() != TemplateURL::OMNIBOX_API_EXTENSION) {
            i->description = l10n_util::GetStringFUTF16(
                IDS_AUTOCOMPLETE_SEARCH_DESCRIPTION, i->description);
          }
          i->description_class.push_back(
              ACMatchClassification(0, ACMatchClassification::DIM));
        }
        last_keyword = i->keyword;
      }
    } else {
      last_keyword.clear();
    }
  }
}

void AutocompleteController::UpdateAssistedQueryStats(
    AutocompleteResult* result) {
  if (result->empty())
    return;

  // Build the impressions string (the AQS part after ".").
  std::string autocompletions;
  int count = 0;
  size_t last_type = base::string16::npos;
  size_t last_subtype = base::string16::npos;
  for (auto match(result->begin()); match != result->end(); ++match) {
    size_t type = base::string16::npos;
    size_t subtype = base::string16::npos;
    AutocompleteMatchToAssistedQuery(
        match->type, match->provider, &type, &subtype);
    if (last_type != base::string16::npos &&
        (type != last_type || subtype != last_subtype)) {
      AppendAvailableAutocompletion(
          last_type, last_subtype, count, &autocompletions);
      count = 1;
    } else {
      count++;
    }
    last_type = type;
    last_subtype = subtype;
  }
  AppendAvailableAutocompletion(
      last_type, last_subtype, count, &autocompletions);
  // Go over all matches and set AQS if the match supports it.
  for (size_t index = 0; index < result->size(); ++index) {
    AutocompleteMatch* match = result->match_at(index);
    const TemplateURL* template_url =
        match->GetTemplateURL(template_url_service_, false);
    if (!template_url || !match->search_terms_args)
      continue;
    std::string selected_index;
    // Prevent trivial suggestions from getting credit for being selected.
    if (!IsTrivialAutocompletion(*match))
      selected_index = base::StringPrintf("%" PRIuS, index);
    match->search_terms_args->assisted_query_stats =
        base::StringPrintf("chrome.%s.%s",
                           selected_index.c_str(),
                           autocompletions.c_str());
    match->destination_url = GURL(template_url->url_ref().ReplaceSearchTerms(
        *match->search_terms_args, template_url_service_->search_terms_data()));
  }
}

void AutocompleteController::NotifyChanged(bool notify_default_match) {
  if (delegate_)
    delegate_->OnResultChanged(notify_default_match);
  if (done_)
    provider_client_->OnAutocompleteControllerResultReady(this);
}

void AutocompleteController::CheckIfDone() {
  for (Providers::const_iterator i(providers_.begin()); i != providers_.end();
       ++i) {
    if (!(*i)->done()) {
      done_ = false;
      return;
    }
  }
  done_ = true;
}

void AutocompleteController::StartExpireTimer() {
  // Amount of time (in ms) between when the user stops typing and
  // when we remove any copied entries. We do this from the time the
  // user stopped typing as some providers (such as SearchProvider)
  // wait for the user to stop typing before they initiate a query.
  const int kExpireTimeMS = 500;

  if (result_.HasCopiedMatches())
    expire_timer_.Start(FROM_HERE,
                        base::TimeDelta::FromMilliseconds(kExpireTimeMS),
                        this, &AutocompleteController::ExpireCopiedEntries);
}

void AutocompleteController::StartStopTimer() {
  stop_timer_.Start(FROM_HERE, stop_timer_duration_,
                    base::BindOnce(&AutocompleteController::StopHelper,
                                   base::Unretained(this), false, true));
}

void AutocompleteController::StopHelper(bool clear_result,
                                        bool due_to_user_inactivity) {
  for (Providers::const_iterator i(providers_.begin()); i != providers_.end();
       ++i) {
    (*i)->Stop(clear_result, due_to_user_inactivity);
  }

  expire_timer_.Stop();
  stop_timer_.Stop();
  done_ = true;
  if (clear_result && !result_.empty()) {
    result_.Reset();
    // NOTE: We pass in false since we're trying to only clear the popup, not
    // touch the edit... this is all a mess and should be cleaned up :(
    NotifyChanged(false);
  }
}

bool AutocompleteController::ShouldCurbKeywordDescriptions(
    const base::string16& keyword) {
  return AutocompleteProvider::InExplicitExperimentalKeywordMode(input_,
                                                                 keyword);
}

bool AutocompleteController::OnMemoryDump(
    const base::trace_event::MemoryDumpArgs& args,
    base::trace_event::ProcessMemoryDump* process_memory_dump) {
  size_t res = 0;

  // provider_client_ seems to be small enough to ignore it.

  // TODO(dyaroshev): implement memory estimation for scoped_refptr in
  // base::trace_event.
  res += std::accumulate(providers_.begin(), providers_.end(), 0u,
                         [](size_t sum, const auto& provider) {
                           return sum + sizeof(AutocompleteProvider) +
                                  provider->EstimateMemoryUsage();
                         });

  res += input_.EstimateMemoryUsage();
  res += result_.EstimateMemoryUsage();

  auto* dump = process_memory_dump->CreateAllocatorDump(
      base::StringPrintf("omnibox/autocomplete_controller/0x%" PRIXPTR,
                         reinterpret_cast<uintptr_t>(this)));
  dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
                  base::trace_event::MemoryAllocatorDump::kUnitsBytes, res);
  return true;
}