chrome/browser/android/omnibox/autocomplete_controller_android.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/browser/android/omnibox/autocomplete_controller_android.h"
   6
   7 #include "base/android/jni_android.h"
   8 #include "base/android/jni_string.h"
   9 #include "base/prefs/pref_service.h"
  10 #include "base/strings/string16.h"
  11 #include "base/strings/utf_string_conversions.h"
  12 #include "base/time/time.h"
  13 #include "base/timer/timer.h"
  14 #include "chrome/browser/autocomplete/autocomplete_classifier.h"
  15 #include "chrome/browser/autocomplete/autocomplete_classifier_factory.h"
  16 #include "chrome/browser/autocomplete/autocomplete_controller.h"
  17 #include "chrome/browser/autocomplete/chrome_autocomplete_scheme_classifier.h"
  18 #include "chrome/browser/autocomplete/shortcuts_backend_factory.h"
  19 #include "chrome/browser/bookmarks/bookmark_model_factory.h"
  20 #include "chrome/browser/browser_process.h"
  21 #include "chrome/browser/chrome_notification_types.h"
  22 #include "chrome/browser/omnibox/omnibox_log.h"
  23 #include "chrome/browser/profiles/incognito_helpers.h"
  24 #include "chrome/browser/profiles/profile_android.h"
  25 #include "chrome/browser/profiles/profile_manager.h"
  26 #include "chrome/browser/search/search.h"
  27 #include "chrome/browser/search_engines/template_url_service_factory.h"
  28 #include "chrome/browser/sessions/session_tab_helper.h"
  29 #include "chrome/browser/ui/search/instant_search_prerenderer.h"
  30 #include "chrome/browser/ui/toolbar/toolbar_model.h"
  31 #include "chrome/common/instant_types.h"
  32 #include "chrome/common/pref_names.h"
  33 #include "chrome/common/url_constants.h"
  34 #include "components/bookmarks/browser/bookmark_model.h"
  35 #include "components/keyed_service/content/browser_context_dependency_manager.h"
  36 #include "components/metrics/proto/omnibox_event.pb.h"
  37 #include "components/omnibox/autocomplete_input.h"
  38 #include "components/omnibox/autocomplete_match.h"
  39 #include "components/omnibox/autocomplete_match_type.h"
  40 #include "components/omnibox/omnibox_field_trial.h"
  41 #include "components/omnibox/search_provider.h"
  42 #include "components/search/search.h"
  43 #include "components/search_engines/template_url_service.h"
  44 #include "content/public/browser/notification_details.h"
  45 #include "content/public/browser/notification_service.h"
  46 #include "content/public/browser/notification_source.h"
  47 #include "content/public/browser/web_contents.h"
  48 #include "content/public/common/url_constants.h"
  49 #include "jni/AutocompleteController_jni.h"
  50 #include "net/base/escape.h"
  51 #include "net/base/net_util.h"
  52 #include "net/base/registry_controlled_domains/registry_controlled_domain.h"
  53
  54 using base::android::AttachCurrentThread;
  55 using base::android::ConvertJavaStringToUTF16;
  56 using base::android::ConvertUTF8ToJavaString;
  57 using base::android::ConvertUTF16ToJavaString;
  58 using metrics::OmniboxEventProto;
  59
  60 namespace {
  61
  62 const int kAndroidAutocompleteProviders =
  63     AutocompleteClassifier::kDefaultOmniboxProviders;
  64
  65 /**
  66  * A prefetcher class responsible for triggering zero suggest prefetch.
  67  * The prefetch occurs as a side-effect of calling StartZeroSuggest() on
  68  * the AutocompleteController object.
  69  */
  70 class ZeroSuggestPrefetcher : public AutocompleteControllerDelegate {
  71  public:
  72   explicit ZeroSuggestPrefetcher(Profile* profile);
  73
  74  private:
  75   virtual ~ZeroSuggestPrefetcher();
  76   void SelfDestruct();
  77
  78   // AutocompleteControllerDelegate:
  79   virtual void OnResultChanged(bool default_match_changed) OVERRIDE;
  80
  81   scoped_ptr<AutocompleteController> controller_;
  82   base::OneShotTimer<ZeroSuggestPrefetcher> expire_timer_;
  83 };
  84
  85 ZeroSuggestPrefetcher::ZeroSuggestPrefetcher(Profile* profile)
  86     : controller_(new AutocompleteController(
  87           profile, TemplateURLServiceFactory::GetForProfile(profile), this,
  88           AutocompleteProvider::TYPE_ZERO_SUGGEST)) {
  89   // Creating an arbitrary fake_request_source to avoid passing in an invalid
  90   // AutocompleteInput object.
  91   base::string16 fake_request_source(base::ASCIIToUTF16(
  92       "http://www.foobarbazblah.com"));
  93   controller_->StartZeroSuggest(AutocompleteInput(
  94       fake_request_source, base::string16::npos, base::string16(),
  95       GURL(fake_request_source), OmniboxEventProto::INVALID_SPEC, false, false,
  96       true, true, ChromeAutocompleteSchemeClassifier(profile)));
  97   // Delete ourselves after 10s. This is enough time to cache results or
  98   // give up if the results haven't been received.
  99   expire_timer_.Start(FROM_HERE,
 100                       base::TimeDelta::FromMilliseconds(10000),
 101                       this, &ZeroSuggestPrefetcher::SelfDestruct);
 102 }
 103
 104 ZeroSuggestPrefetcher::~ZeroSuggestPrefetcher() {
 105 }
 106
 107 void ZeroSuggestPrefetcher::SelfDestruct() {
 108   delete this;
 109 }
 110
 111 void ZeroSuggestPrefetcher::OnResultChanged(bool default_match_changed) {
 112   // Nothing to do here, the results have been cached.
 113   // We don't want to trigger deletion here because this is being called by the
 114   // AutocompleteController object.
 115 }
 116
 117 }  // namespace
 118
 119 AutocompleteControllerAndroid::AutocompleteControllerAndroid(Profile* profile)
 120     : autocomplete_controller_(new AutocompleteController(
 121           profile, TemplateURLServiceFactory::GetForProfile(profile), this,
 122           kAndroidAutocompleteProviders)),
 123       inside_synchronous_start_(false),
 124       profile_(profile) {
 125 }
 126
 127 void AutocompleteControllerAndroid::Start(JNIEnv* env,
 128                                           jobject obj,
 129                                           jstring j_text,
 130                                           jstring j_desired_tld,
 131                                           jstring j_current_url,
 132                                           bool prevent_inline_autocomplete,
 133                                           bool prefer_keyword,
 134                                           bool allow_exact_keyword_match,
 135                                           bool want_asynchronous_matches) {
 136   if (!autocomplete_controller_)
 137     return;
 138
 139   base::string16 desired_tld;
 140   GURL current_url;
 141   if (j_current_url != NULL)
 142     current_url = GURL(ConvertJavaStringToUTF16(env, j_current_url));
 143   if (j_desired_tld != NULL)
 144     desired_tld = ConvertJavaStringToUTF16(env, j_desired_tld);
 145   base::string16 text = ConvertJavaStringToUTF16(env, j_text);
 146   OmniboxEventProto::PageClassification page_classification =
 147       OmniboxEventProto::OTHER;
 148   input_ = AutocompleteInput(
 149       text, base::string16::npos, desired_tld, current_url, page_classification,
 150       prevent_inline_autocomplete, prefer_keyword, allow_exact_keyword_match,
 151       want_asynchronous_matches, ChromeAutocompleteSchemeClassifier(profile_));
 152   autocomplete_controller_->Start(input_);
 153 }
 154
 155 ScopedJavaLocalRef<jobject> AutocompleteControllerAndroid::Classify(
 156     JNIEnv* env,
 157     jobject obj,
 158     jstring j_text) {
 159   return GetTopSynchronousResult(env, obj, j_text, true);
 160 }
 161
 162 void AutocompleteControllerAndroid::StartZeroSuggest(
 163     JNIEnv* env,
 164     jobject obj,
 165     jstring j_omnibox_text,
 166     jstring j_current_url,
 167     jboolean is_query_in_omnibox,
 168     jboolean focused_from_fakebox) {
 169   if (!autocomplete_controller_)
 170     return;
 171
 172   base::string16 url = ConvertJavaStringToUTF16(env, j_current_url);
 173   const GURL current_url = GURL(url);
 174   base::string16 omnibox_text = ConvertJavaStringToUTF16(env, j_omnibox_text);
 175
 176   // If omnibox text is empty, set it to the current URL for the purposes of
 177   // populating the verbatim match.
 178   if (omnibox_text.empty())
 179     omnibox_text = url;
 180
 181   input_ = AutocompleteInput(
 182       omnibox_text, base::string16::npos, base::string16(), current_url,
 183       ClassifyPage(current_url, is_query_in_omnibox, focused_from_fakebox),
 184       false, false, true, true, ChromeAutocompleteSchemeClassifier(profile_));
 185   autocomplete_controller_->StartZeroSuggest(input_);
 186 }
 187
 188 void AutocompleteControllerAndroid::Stop(JNIEnv* env,
 189                                          jobject obj,
 190                                          bool clear_results) {
 191   if (autocomplete_controller_ != NULL)
 192     autocomplete_controller_->Stop(clear_results);
 193 }
 194
 195 void AutocompleteControllerAndroid::ResetSession(JNIEnv* env, jobject obj) {
 196   if (autocomplete_controller_ != NULL)
 197     autocomplete_controller_->ResetSession();
 198 }
 199
 200 void AutocompleteControllerAndroid::OnSuggestionSelected(
 201     JNIEnv* env,
 202     jobject obj,
 203     jint selected_index,
 204     jstring j_current_url,
 205     jboolean is_query_in_omnibox,
 206     jboolean focused_from_fakebox,
 207     jlong elapsed_time_since_first_modified,
 208     jobject j_web_contents) {
 209   base::string16 url = ConvertJavaStringToUTF16(env, j_current_url);
 210   const GURL current_url = GURL(url);
 211   OmniboxEventProto::PageClassification current_page_classification =
 212       ClassifyPage(current_url, is_query_in_omnibox, focused_from_fakebox);
 213   const base::TimeTicks& now(base::TimeTicks::Now());
 214   content::WebContents* web_contents =
 215       content::WebContents::FromJavaWebContents(j_web_contents);
 216
 217   OmniboxLog log(
 218       input_.text(),
 219       false, /* don't know */
 220       input_.type(),
 221       true,
 222       selected_index,
 223       false,
 224       SessionTabHelper::IdForTab(web_contents),
 225       current_page_classification,
 226       base::TimeDelta::FromMilliseconds(elapsed_time_since_first_modified),
 227       base::string16::npos,
 228       now - autocomplete_controller_->last_time_default_match_changed(),
 229       autocomplete_controller_->result());
 230   autocomplete_controller_->AddProvidersInfo(&log.providers_info);
 231
 232   content::NotificationService::current()->Notify(
 233       chrome::NOTIFICATION_OMNIBOX_OPENED_URL,
 234       content::Source<Profile>(profile_),
 235       content::Details<OmniboxLog>(&log));
 236 }
 237
 238 void AutocompleteControllerAndroid::DeleteSuggestion(JNIEnv* env,
 239                                                      jobject obj,
 240                                                      int selected_index) {
 241   const AutocompleteResult& result = autocomplete_controller_->result();
 242   const AutocompleteMatch& match = result.match_at(selected_index);
 243   if (match.SupportsDeletion())
 244     autocomplete_controller_->DeleteMatch(match);
 245 }
 246
 247 ScopedJavaLocalRef<jstring> AutocompleteControllerAndroid::
 248     UpdateMatchDestinationURLWithQueryFormulationTime(
 249         JNIEnv* env,
 250         jobject obj,
 251         jint selected_index,
 252         jlong elapsed_time_since_input_change) {
 253   // In rare cases, we navigate to cached matches and the underlying result
 254   // has already been cleared, in that case ignore the URL update.
 255   if (autocomplete_controller_->result().empty())
 256     return ScopedJavaLocalRef<jstring>();
 257
 258   AutocompleteMatch match(
 259       autocomplete_controller_->result().match_at(selected_index));
 260   autocomplete_controller_->UpdateMatchDestinationURLWithQueryFormulationTime(
 261       base::TimeDelta::FromMilliseconds(elapsed_time_since_input_change),
 262       &match);
 263   return ConvertUTF8ToJavaString(env, match.destination_url.spec());
 264 }
 265
 266 ScopedJavaLocalRef<jobject>
 267 AutocompleteControllerAndroid::GetTopSynchronousMatch(JNIEnv* env,
 268                                                       jobject obj,
 269                                                       jstring query) {
 270   return GetTopSynchronousResult(env, obj, query, false);
 271 }
 272
 273 void AutocompleteControllerAndroid::Shutdown() {
 274   autocomplete_controller_.reset();
 275
 276   JNIEnv* env = AttachCurrentThread();
 277   ScopedJavaLocalRef<jobject> java_bridge =
 278       weak_java_autocomplete_controller_android_.get(env);
 279   if (java_bridge.obj())
 280     Java_AutocompleteController_notifyNativeDestroyed(env, java_bridge.obj());
 281
 282   weak_java_autocomplete_controller_android_.reset();
 283 }
 284
 285 // static
 286 AutocompleteControllerAndroid*
 287 AutocompleteControllerAndroid::Factory::GetForProfile(
 288     Profile* profile, JNIEnv* env, jobject obj) {
 289   AutocompleteControllerAndroid* bridge =
 290       static_cast<AutocompleteControllerAndroid*>(
 291           GetInstance()->GetServiceForBrowserContext(profile, true));
 292   bridge->InitJNI(env, obj);
 293   return bridge;
 294 }
 295
 296 AutocompleteControllerAndroid::Factory*
 297 AutocompleteControllerAndroid::Factory::GetInstance() {
 298   return Singleton<AutocompleteControllerAndroid::Factory>::get();
 299 }
 300
 301 content::BrowserContext*
 302 AutocompleteControllerAndroid::Factory::GetBrowserContextToUse(
 303     content::BrowserContext* context) const {
 304   return chrome::GetBrowserContextOwnInstanceInIncognito(context);
 305 }
 306
 307 AutocompleteControllerAndroid::Factory::Factory()
 308     : BrowserContextKeyedServiceFactory(
 309           "AutocompleteControllerAndroid",
 310           BrowserContextDependencyManager::GetInstance()) {
 311   DependsOn(ShortcutsBackendFactory::GetInstance());
 312 }
 313
 314 AutocompleteControllerAndroid::Factory::~Factory() {
 315 }
 316
 317 KeyedService* AutocompleteControllerAndroid::Factory::BuildServiceInstanceFor(
 318     content::BrowserContext* profile) const {
 319   return new AutocompleteControllerAndroid(static_cast<Profile*>(profile));
 320 }
 321
 322 AutocompleteControllerAndroid::~AutocompleteControllerAndroid() {
 323 }
 324
 325 void AutocompleteControllerAndroid::InitJNI(JNIEnv* env, jobject obj) {
 326   weak_java_autocomplete_controller_android_ =
 327       JavaObjectWeakGlobalRef(env, obj);
 328 }
 329
 330 void AutocompleteControllerAndroid::OnResultChanged(
 331     bool default_match_changed) {
 332   if (!autocomplete_controller_)
 333     return;
 334
 335   const AutocompleteResult& result = autocomplete_controller_->result();
 336   const AutocompleteResult::const_iterator default_match(
 337       result.default_match());
 338   if ((default_match != result.end()) && default_match_changed &&
 339       chrome::IsInstantExtendedAPIEnabled() &&
 340       chrome::ShouldPrefetchSearchResults()) {
 341     InstantSuggestion prefetch_suggestion;
 342     // If the default match should be prefetched, do that.
 343     if (SearchProvider::ShouldPrefetch(*default_match)) {
 344       prefetch_suggestion.text = default_match->contents;
 345       prefetch_suggestion.metadata =
 346           SearchProvider::GetSuggestMetadata(*default_match);
 347     }
 348     // Send the prefetch suggestion unconditionally to the Instant search base
 349     // page. If there is no suggestion to prefetch, we need to send a blank
 350     // query to clear the prefetched results.
 351     InstantSearchPrerenderer* prerenderer =
 352         InstantSearchPrerenderer::GetForProfile(profile_);
 353     if (prerenderer)
 354       prerenderer->Prerender(prefetch_suggestion);
 355   }
 356   if (!inside_synchronous_start_)
 357     NotifySuggestionsReceived(autocomplete_controller_->result());
 358 }
 359
 360 void AutocompleteControllerAndroid::NotifySuggestionsReceived(
 361     const AutocompleteResult& autocomplete_result) {
 362   JNIEnv* env = AttachCurrentThread();
 363   ScopedJavaLocalRef<jobject> java_bridge =
 364       weak_java_autocomplete_controller_android_.get(env);
 365   if (!java_bridge.obj())
 366     return;
 367
 368   ScopedJavaLocalRef<jobject> suggestion_list_obj =
 369       Java_AutocompleteController_createOmniboxSuggestionList(
 370           env, autocomplete_result.size());
 371   for (size_t i = 0; i < autocomplete_result.size(); ++i) {
 372     ScopedJavaLocalRef<jobject> j_omnibox_suggestion =
 373         BuildOmniboxSuggestion(env, autocomplete_result.match_at(i));
 374     Java_AutocompleteController_addOmniboxSuggestionToList(
 375         env, suggestion_list_obj.obj(), j_omnibox_suggestion.obj());
 376   }
 377
 378   // Get the inline-autocomplete text.
 379   const AutocompleteResult::const_iterator default_match(
 380       autocomplete_result.default_match());
 381   base::string16 inline_autocomplete_text;
 382   if (default_match != autocomplete_result.end()) {
 383     inline_autocomplete_text = default_match->inline_autocompletion;
 384   }
 385   ScopedJavaLocalRef<jstring> inline_text =
 386       ConvertUTF16ToJavaString(env, inline_autocomplete_text);
 387   jlong j_autocomplete_result =
 388       reinterpret_cast<intptr_t>(&(autocomplete_result));
 389   Java_AutocompleteController_onSuggestionsReceived(env,
 390                                                     java_bridge.obj(),
 391                                                     suggestion_list_obj.obj(),
 392                                                     inline_text.obj(),
 393                                                     j_autocomplete_result);
 394 }
 395
 396 OmniboxEventProto::PageClassification
 397 AutocompleteControllerAndroid::ClassifyPage(const GURL& gurl,
 398                                             bool is_query_in_omnibox,
 399                                             bool focused_from_fakebox) const {
 400   if (!gurl.is_valid())
 401     return OmniboxEventProto::INVALID_SPEC;
 402
 403   const std::string& url = gurl.spec();
 404
 405   if (gurl.SchemeIs(content::kChromeUIScheme) &&
 406       gurl.host() == chrome::kChromeUINewTabHost) {
 407     return OmniboxEventProto::NTP;
 408   }
 409
 410   if (url == chrome::kChromeUINativeNewTabURL) {
 411     return focused_from_fakebox ?
 412         OmniboxEventProto::INSTANT_NTP_WITH_FAKEBOX_AS_STARTING_FOCUS :
 413         OmniboxEventProto::INSTANT_NTP_WITH_OMNIBOX_AS_STARTING_FOCUS;
 414   }
 415
 416   if (url == url::kAboutBlankURL)
 417     return OmniboxEventProto::BLANK;
 418
 419   if (url == profile_->GetPrefs()->GetString(prefs::kHomePage))
 420     return OmniboxEventProto::HOME_PAGE;
 421
 422   if (is_query_in_omnibox)
 423     return OmniboxEventProto::SEARCH_RESULT_PAGE_DOING_SEARCH_TERM_REPLACEMENT;
 424
 425   bool is_search_url = TemplateURLServiceFactory::GetForProfile(profile_)->
 426       IsSearchResultsPageFromDefaultSearchProvider(gurl);
 427   if (is_search_url)
 428     return OmniboxEventProto::SEARCH_RESULT_PAGE_NO_SEARCH_TERM_REPLACEMENT;
 429
 430   return OmniboxEventProto::OTHER;
 431 }
 432
 433 ScopedJavaLocalRef<jobject>
 434 AutocompleteControllerAndroid::BuildOmniboxSuggestion(
 435     JNIEnv* env,
 436     const AutocompleteMatch& match) {
 437   ScopedJavaLocalRef<jstring> contents =
 438       ConvertUTF16ToJavaString(env, match.contents);
 439   ScopedJavaLocalRef<jstring> description =
 440       ConvertUTF16ToJavaString(env, match.description);
 441   ScopedJavaLocalRef<jstring> answer_contents =
 442       ConvertUTF16ToJavaString(env, match.answer_contents);
 443   ScopedJavaLocalRef<jstring> answer_type =
 444       ConvertUTF16ToJavaString(env, match.answer_type);
 445   ScopedJavaLocalRef<jstring> fill_into_edit =
 446       ConvertUTF16ToJavaString(env, match.fill_into_edit);
 447   ScopedJavaLocalRef<jstring> destination_url =
 448       ConvertUTF8ToJavaString(env, match.destination_url.spec());
 449   // Note that we are also removing 'www' host from formatted url.
 450   ScopedJavaLocalRef<jstring> formatted_url = ConvertUTF16ToJavaString(env,
 451       FormatURLUsingAcceptLanguages(match.stripped_destination_url));
 452   BookmarkModel* bookmark_model = BookmarkModelFactory::GetForProfile(profile_);
 453   return Java_AutocompleteController_buildOmniboxSuggestion(
 454       env,
 455       match.type,
 456       match.relevance,
 457       match.transition,
 458       contents.obj(),
 459       description.obj(),
 460       answer_contents.obj(),
 461       answer_type.obj(),
 462       fill_into_edit.obj(),
 463       destination_url.obj(),
 464       formatted_url.obj(),
 465       bookmark_model && bookmark_model->IsBookmarked(match.destination_url),
 466       match.SupportsDeletion());
 467 }
 468
 469 base::string16 AutocompleteControllerAndroid::FormatURLUsingAcceptLanguages(
 470     GURL url) {
 471   if (profile_ == NULL)
 472     return base::string16();
 473
 474   std::string languages(
 475       profile_->GetPrefs()->GetString(prefs::kAcceptLanguages));
 476
 477   return net::FormatUrl(url, languages, net::kFormatUrlOmitAll,
 478       net::UnescapeRule::SPACES, NULL, NULL, NULL);
 479 }
 480
 481 ScopedJavaLocalRef<jobject>
 482 AutocompleteControllerAndroid::GetTopSynchronousResult(
 483     JNIEnv* env,
 484     jobject obj,
 485     jstring j_text,
 486     bool prevent_inline_autocomplete) {
 487   if (!autocomplete_controller_)
 488     return ScopedJavaLocalRef<jobject>();
 489
 490   inside_synchronous_start_ = true;
 491   Start(env,
 492         obj,
 493         j_text,
 494         NULL,
 495         NULL,
 496         prevent_inline_autocomplete,
 497         false,
 498         false,
 499         false);
 500   inside_synchronous_start_ = false;
 501   DCHECK(autocomplete_controller_->done());
 502   const AutocompleteResult& result = autocomplete_controller_->result();
 503   if (result.empty())
 504     return ScopedJavaLocalRef<jobject>();
 505
 506   return BuildOmniboxSuggestion(env, *result.begin());
 507 }
 508
 509 static jlong Init(JNIEnv* env, jobject obj, jobject jprofile) {
 510   Profile* profile = ProfileAndroid::FromProfileAndroid(jprofile);
 511   if (!profile)
 512     return 0;
 513
 514   AutocompleteControllerAndroid* native_bridge =
 515       AutocompleteControllerAndroid::Factory::GetForProfile(profile, env, obj);
 516   return reinterpret_cast<intptr_t>(native_bridge);
 517 }
 518
 519 static jstring QualifyPartialURLQuery(
 520     JNIEnv* env, jclass clazz, jstring jquery) {
 521   Profile* profile = ProfileManager::GetActiveUserProfile();
 522   if (!profile)
 523     return NULL;
 524   AutocompleteMatch match;
 525   base::string16 query_string(ConvertJavaStringToUTF16(env, jquery));
 526   AutocompleteClassifierFactory::GetForProfile(profile)->Classify(
 527       query_string,
 528       false,
 529       false,
 530       OmniboxEventProto::INVALID_SPEC,
 531       &match,
 532       NULL);
 533   if (!match.destination_url.is_valid())
 534     return NULL;
 535
 536   // Only return a URL if the match is a URL type.
 537   if (match.type != AutocompleteMatchType::URL_WHAT_YOU_TYPED &&
 538       match.type != AutocompleteMatchType::HISTORY_URL &&
 539       match.type != AutocompleteMatchType::NAVSUGGEST)
 540     return NULL;
 541
 542   // As we are returning to Java, it is fine to call Release().
 543   return ConvertUTF8ToJavaString(env, match.destination_url.spec()).Release();
 544 }
 545
 546 static void PrefetchZeroSuggestResults(JNIEnv* env, jclass clazz) {
 547   Profile* profile = ProfileManager::GetActiveUserProfile();
 548   if (!profile)
 549     return;
 550
 551   if (!OmniboxFieldTrial::InZeroSuggestPersonalizedFieldTrial())
 552     return;
 553
 554   // ZeroSuggestPrefetcher deletes itself after it's done prefetching.
 555   new ZeroSuggestPrefetcher(profile);
 556 }
 557
 558 // Register native methods
 559 bool RegisterAutocompleteControllerAndroid(JNIEnv* env) {
 560   return RegisterNativesImpl(env);
 561 }