Add ContextualSuggestionsService to Omnibox.

This CL was cloned from https://codereview.chromium.org/2965173002/.

Create a new class `ContextualSuggestionsService` to fetch experimental
contextual suggestions for the omnibox.

Bug: 692471,609084, 750985
Change-Id: Ib54be91b1c0e2cb1fcdaf9a7a43b71984e5c358c
Reviewed-on: https://chromium-review.googlesource.com/576284
Commit-Queue: Owen Min <zmin@chromium.org>
Reviewed-by: Roger Tawa <rogerta@chromium.org>
Reviewed-by: Rohit Rao (ping after 24h) <rohitrao@chromium.org>
Reviewed-by: Mark Pearson <mpearson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491762}

chrome/browser/BUILD.gn

@@ -83,6 +83,8 @@ split_static_library("browser") {
     "autocomplete/chrome_autocomplete_provider_client.h",
     "autocomplete/chrome_autocomplete_scheme_classifier.cc",
     "autocomplete/chrome_autocomplete_scheme_classifier.h",
+    "autocomplete/contextual_suggestions_service_factory.cc",
+    "autocomplete/contextual_suggestions_service_factory.h",
     "autocomplete/in_memory_url_index_factory.cc",
     "autocomplete/in_memory_url_index_factory.h",
     "autocomplete/shortcuts_backend_factory.cc",

chrome/browser/autocomplete/chrome_autocomplete_provider_client.cc

@@ -12,6 +12,7 @@
 #include "base/strings/utf_string_conversions.h"
 #include "build/build_config.h"
 #include "chrome/browser/autocomplete/autocomplete_classifier_factory.h"
+#include "chrome/browser/autocomplete/contextual_suggestions_service_factory.h"
 #include "chrome/browser/autocomplete/in_memory_url_index_factory.h"
 #include "chrome/browser/autocomplete/shortcuts_backend_factory.h"
 #include "chrome/browser/bitmap_fetcher/bitmap_fetcher_service.h"
@@ -133,6 +134,11 @@ ChromeAutocompleteProviderClient::GetTemplateURLService() const {
   return TemplateURLServiceFactory::GetForProfile(profile_);
 }
 
+ContextualSuggestionsService*
+ChromeAutocompleteProviderClient::GetContextualSuggestionsService() const {
+  return ContextualSuggestionsServiceFactory::GetForProfile(profile_);
+}
+
 const
 SearchTermsData& ChromeAutocompleteProviderClient::GetSearchTermsData() const {
   return search_terms_data_;

chrome/browser/autocomplete/chrome_autocomplete_provider_client.h

@@ -33,6 +33,8 @@ class ChromeAutocompleteProviderClient : public AutocompleteProviderClient {
   InMemoryURLIndex* GetInMemoryURLIndex() override;
   TemplateURLService* GetTemplateURLService() override;
   const TemplateURLService* GetTemplateURLService() const override;
+  ContextualSuggestionsService* GetContextualSuggestionsService()
+      const override;
   const SearchTermsData& GetSearchTermsData() const override;
   scoped_refptr<ShortcutsBackend> GetShortcutsBackend() override;
   scoped_refptr<ShortcutsBackend> GetShortcutsBackendIfExists() override;

chrome/browser/autocomplete/contextual_suggestions_service_factory.cc

+// Copyright 2017 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 "chrome/browser/autocomplete/contextual_suggestions_service_factory.h"
+
+#include "base/memory/singleton.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/signin/profile_oauth2_token_service_factory.h"
+#include "chrome/browser/signin/signin_manager_factory.h"
+#include "components/keyed_service/content/browser_context_dependency_manager.h"
+#include "components/omnibox/browser/contextual_suggestions_service.h"
+#include "components/signin/core/browser/profile_oauth2_token_service.h"
+#include "components/signin/core/browser/signin_manager.h"
+
+// static
+ContextualSuggestionsService*
+ContextualSuggestionsServiceFactory::GetForProfile(Profile* profile) {
+  return static_cast<ContextualSuggestionsService*>(
+      GetInstance()->GetServiceForBrowserContext(profile, true));
+}
+
+// static
+ContextualSuggestionsServiceFactory*
+ContextualSuggestionsServiceFactory::GetInstance() {
+  return base::Singleton<ContextualSuggestionsServiceFactory>::get();
+}
+
+KeyedService* ContextualSuggestionsServiceFactory::BuildServiceInstanceFor(
+    content::BrowserContext* context) const {
+  Profile* profile = Profile::FromBrowserContext(context);
+  SigninManagerBase* signin_manager =
+      SigninManagerFactory::GetForProfile(profile);
+  ProfileOAuth2TokenService* token_service =
+      ProfileOAuth2TokenServiceFactory::GetForProfile(profile);
+  return new ContextualSuggestionsService(signin_manager, token_service,
+                                          profile->GetRequestContext());
+}
+
+ContextualSuggestionsServiceFactory::ContextualSuggestionsServiceFactory()
+    : BrowserContextKeyedServiceFactory(
+          "ContextualSuggestionsService",
+          BrowserContextDependencyManager::GetInstance()) {
+  DependsOn(SigninManagerFactory::GetInstance());
+  DependsOn(ProfileOAuth2TokenServiceFactory::GetInstance());
+}
+
+ContextualSuggestionsServiceFactory::~ContextualSuggestionsServiceFactory() {}

chrome/browser/autocomplete/contextual_suggestions_service_factory.h

+// Copyright 2017 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.
+
+#ifndef CHROME_BROWSER_AUTOCOMPLETE_CONTEXTUAL_SUGGESTIONS_SERVICE_FACTORY_H_
+#define CHROME_BROWSER_AUTOCOMPLETE_CONTEXTUAL_SUGGESTIONS_SERVICE_FACTORY_H_
+
+#include "base/macros.h"
+#include "base/memory/singleton.h"
+#include "components/keyed_service/content/browser_context_keyed_service_factory.h"
+
+class ContextualSuggestionsService;
+class Profile;
+
+class ContextualSuggestionsServiceFactory
+    : public BrowserContextKeyedServiceFactory {
+ public:
+  static ContextualSuggestionsService* GetForProfile(Profile* profile);
+  static ContextualSuggestionsServiceFactory* GetInstance();
+
+ private:
+  friend struct base::DefaultSingletonTraits<
+      ContextualSuggestionsServiceFactory>;
+
+  ContextualSuggestionsServiceFactory();
+  ~ContextualSuggestionsServiceFactory() override;
+
+  // Overrides from BrowserContextKeyedServiceFactory:
+  KeyedService* BuildServiceInstanceFor(
+      content::BrowserContext* context) const override;
+
+  DISALLOW_COPY_AND_ASSIGN(ContextualSuggestionsServiceFactory);
+};
+
+#endif  // CHROME_BROWSER_AUTOCOMPLETE_CONTEXTUAL_SUGGESTIONS_SERVICE_FACTORY_H_

components/omnibox/browser/BUILD.gn

@@ -52,6 +52,8 @@ static_library("browser") {
     "builtin_provider.h",
     "clipboard_url_provider.cc",
     "clipboard_url_provider.h",
+    "contextual_suggestions_service.cc",
+    "contextual_suggestions_service.h",
     "history_match.cc",
     "history_match.h",
     "history_provider.cc",
@@ -152,6 +154,7 @@ static_library("browser") {
     "//components/search",
     "//components/search_engines",
     "//components/sessions",
+    "//components/signin/core/browser",
     "//components/strings",
     "//components/toolbar",
     "//components/url_formatter",

components/omnibox/browser/DEPS

@@ -15,6 +15,7 @@ include_rules = [
   "+components/search",
   "+components/search_engines",
   "+components/sessions",
+  "+components/signin/core/browser",
   "+components/strings/grit/components_strings.h",
   "+components/toolbar",
   "+components/url_formatter",

components/omnibox/browser/autocomplete_provider_client.h

@@ -19,6 +19,7 @@ class AutocompleteController;
 struct AutocompleteMatch;
 class AutocompleteClassifier;
 class AutocompleteSchemeClassifier;
+class ContextualSuggestionsService;
 class GURL;
 class InMemoryURLIndex;
 class KeywordProvider;
@@ -60,6 +61,8 @@ class AutocompleteProviderClient {
   virtual InMemoryURLIndex* GetInMemoryURLIndex() = 0;
   virtual TemplateURLService* GetTemplateURLService() = 0;
   virtual const TemplateURLService* GetTemplateURLService() const = 0;
+  virtual ContextualSuggestionsService* GetContextualSuggestionsService()
+      const = 0;
   virtual const SearchTermsData& GetSearchTermsData() const = 0;
   virtual scoped_refptr<ShortcutsBackend> GetShortcutsBackend() = 0;
   virtual scoped_refptr<ShortcutsBackend> GetShortcutsBackendIfExists() = 0;

components/omnibox/browser/base_search_provider_unittest.cc

@@ -10,6 +10,7 @@
 #include "base/strings/string16.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/test/scoped_task_environment.h"
 #include "components/omnibox/browser/autocomplete_match.h"
 #include "components/omnibox/browser/autocomplete_match_type.h"
 #include "components/omnibox/browser/autocomplete_scheme_classifier.h"
@@ -82,6 +83,7 @@ class BaseSearchProviderTest : public testing::Test {
         AutocompleteProvider::TYPE_SEARCH, client_.get());
   }
 
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
   scoped_refptr<NiceMock<TestBaseSearchProvider> > provider_;
   std::unique_ptr<NiceMock<MockAutocompleteProviderClient>> client_;
 };

components/omnibox/browser/contextual_suggestions_service.h

+// Copyright 2017 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.
+
+#ifndef COMPONENTS_OMNIBOX_BROWSER_CONTEXTUAL_SUGGESTIONS_SERVICE_H_
+#define COMPONENTS_OMNIBOX_BROWSER_CONTEXTUAL_SUGGESTIONS_SERVICE_H_
+
+#include <memory>
+#include <string>
+
+#include "components/keyed_service/core/keyed_service.h"
+#include "components/signin/core/browser/access_token_fetcher.h"
+#include "net/url_request/url_fetcher_delegate.h"
+#include "url/gurl.h"
+
+class OAuth2TokenService;
+class SigninManagerBase;
+class TemplateURLService;
+
+// A service to fetch suggestions from a remote endpoint given a URL.
+class ContextualSuggestionsService : public KeyedService {
+ public:
+  // |signin_manager| and |token_service| may be null but only unauthenticated
+  // requests will issued.
+  // |request_context|  may be null, but some services may be disabled.
+  ContextualSuggestionsService(SigninManagerBase* signin_manager,
+                               OAuth2TokenService* token_service,
+                               net::URLRequestContextGetter* request_context);
+
+  ~ContextualSuggestionsService() override;
+
+  using ContextualSuggestionsCallback =
+      base::OnceCallback<void(std::unique_ptr<net::URLFetcher> fetcher)>;
+
+  // Creates a fetcher for contextual suggestions for |current_url| and passes
+  // the fetcher to the provided callback.
+  //
+  // |current_url| may be empty, in which case the system will never use the
+  // experimental suggestions service. It's possible the non-experimental
+  // service may decide to offer general-purpose suggestions.
+  //
+  // |template_url_service| may be null, but some services may be disabled.
+  //
+  // |fetcher_delegate| is used to create a fetcher that is used to perform a
+  // network request. It uses a number of signals to create the fetcher,
+  // including field trial / experimental parameters, and it may pass a nullptr
+  // fetcher to the callback.
+  //
+  // |callback| is called with the fetcher produced by the |fetcher_delegate| as
+  // an argument. |callback| is called with a nullptr argument if:
+  //   * The service is waiting for a previously-requested authentication token.
+  //   * The authentication token had any issues.
+  //
+  // This method sends a request for an OAuth2 token and temporarily
+  // instantiates |token_fetcher_|.
+  void CreateContextualSuggestionsRequest(
+      const std::string& current_url,
+      const TemplateURLService* template_url_service,
+      net::URLFetcherDelegate* fetcher_delegate,
+      ContextualSuggestionsCallback callback);
+
+  // Returns a URL representing the address of the server where the zero suggest
+  // request is being sent. Does not take into account whether sending this
+  // request is prohibited (e.g. in an incognito window).
+  // Returns an invalid URL (i.e.: GURL::is_valid() == false) in case of an
+  // error.
+  //
+  // |current_url| is the page the user is currently browsing and may be empty.
+  //
+  // Note that this method is public and is also used by ZeroSuggestProvider for
+  // suggestions that do not take |current_url| into consideration.
+  static GURL ContextualSuggestionsUrl(
+      const std::string& current_url,
+      const TemplateURLService* template_url_service);
+
+ private:
+  // Returns a URL representing the address of the server where the zero suggest
+  // requests are being redirected when serving experimental suggestions.
+  //
+  // Returns a valid URL only if all the folowing conditions are true:
+  // * The |current_url| is non-empty.
+  // * The |default_provider| is Google.
+  // * The user is in the ZeroSuggestRedirectToChrome field trial.
+  // * The field trial provides a valid server address where the suggest request
+  //   is redirected.
+  // * The suggest request is over HTTPS. This avoids leaking the current page
+  //   URL or personal data in unencrypted network traffic.
+  // Note: these checks are in addition to CanSendUrl() on the default
+  // contextual suggestion URL.
+  GURL ExperimentalZeroSuggestURL(
+      const std::string& current_url,
+      const TemplateURLService* template_url_service) const;
+
+  // Creates an HTTP GET request for contextual suggestions. The returned
+  // fetcher does not include a header corresponding with an authorization
+  // token.
+  std::unique_ptr<net::URLFetcher> CreateRequest(
+      const GURL& suggest_url,
+      bool is_experimental,
+      net::URLFetcherDelegate* fetcher_delegate) const;
+
+  // Called when an access token request completes (successfully or not).
+  void AccessTokenAvailable(std::unique_ptr<net::URLFetcher> fetcher,
+                            ContextualSuggestionsCallback callback,
+                            const GoogleServiceAuthError& error,
+                            const std::string& access_token);
+
+  net::URLRequestContextGetter* request_context_;
+  SigninManagerBase* signin_manager_;
+  OAuth2TokenService* token_service_;
+
+  // Helper for fetching OAuth2 access tokens. This is non-null when an access
+  // token request is currently in progress.
+  std::unique_ptr<AccessTokenFetcher> token_fetcher_;
+
+  DISALLOW_COPY_AND_ASSIGN(ContextualSuggestionsService);
+};
+
+#endif  // COMPONENTS_OMNIBOX_BROWSER_CONTEXTUAL_SUGGESTIONS_SERVICE_H_

components/omnibox/browser/keyword_provider_unittest.cc

@@ -13,6 +13,7 @@
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/field_trial.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/test/scoped_task_environment.h"
 #include "components/metrics/proto/omnibox_event.pb.h"
 #include "components/omnibox/browser/autocomplete_match.h"
 #include "components/omnibox/browser/autocomplete_scheme_classifier.h"
@@ -84,6 +85,7 @@ class KeywordProviderTest : public testing::Test {
  protected:
   static const TemplateURLService::Initializer kTestData[];
 
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
   std::unique_ptr<base::FieldTrialList> field_trial_list_;
   scoped_refptr<KeywordProvider> kw_provider_;
   std::unique_ptr<MockAutocompleteProviderClient> client_;

components/omnibox/browser/mock_autocomplete_provider_client.cc

@@ -4,7 +4,13 @@
 
 #include "components/omnibox/browser/mock_autocomplete_provider_client.h"
 
+#include "base/memory/ptr_util.h"
+
 MockAutocompleteProviderClient::MockAutocompleteProviderClient() {
+  contextual_suggestions_service_ =
+      base::MakeUnique<ContextualSuggestionsService>(
+          /*signin_manager=*/nullptr, /*token_service=*/nullptr,
+          GetRequestContext());
 }
 
 MockAutocompleteProviderClient::~MockAutocompleteProviderClient() {

components/omnibox/browser/mock_autocomplete_provider_client.h

@@ -11,6 +11,7 @@
 #include "base/macros.h"
 #include "components/omnibox/browser/autocomplete_provider_client.h"
 #include "components/omnibox/browser/autocomplete_scheme_classifier.h"
+#include "components/omnibox/browser/contextual_suggestions_service.h"
 #include "components/search_engines/search_terms_data.h"
 #include "components/search_engines/template_url_service.h"
 #include "testing/gmock/include/gmock/gmock.h"
@@ -43,6 +44,11 @@ class MockAutocompleteProviderClient : public AutocompleteProviderClient {
   const TemplateURLService* GetTemplateURLService() const override {
     return template_url_service_.get();
   }
+  ContextualSuggestionsService* GetContextualSuggestionsService()
+      const override {
+    return contextual_suggestions_service_.get();
+  }
+
   std::unique_ptr<KeywordExtensionsDelegate> GetKeywordExtensionsDelegate(
       KeywordProvider* keyword_provider) override {
     return nullptr;
@@ -85,6 +91,7 @@ class MockAutocompleteProviderClient : public AutocompleteProviderClient {
   }
 
  private:
+  std::unique_ptr<ContextualSuggestionsService> contextual_suggestions_service_;
   std::unique_ptr<TemplateURLService> template_url_service_;
 
   DISALLOW_COPY_AND_ASSIGN(MockAutocompleteProviderClient);

components/omnibox/browser/omnibox_field_trial.cc

@@ -317,6 +317,14 @@ bool OmniboxFieldTrial::InZeroSuggestPersonalizedFieldTrial() {
       kZeroSuggestVariantRule) == "Personalized";
 }
 
+// static
+int OmniboxFieldTrial::GetZeroSuggestRedirectToChromeExperimentId() {
+  return base::GetFieldTrialParamByFeatureAsInt(
+      omnibox::kZeroSuggestRedirectToChrome,
+      OmniboxFieldTrial::kZeroSuggestRedirectToChromeExperimentIdParam,
+      /*default_value=*/-1);
+}
+
 bool OmniboxFieldTrial::ShortcutsScoringMaxRelevance(
     OmniboxEventProto::PageClassification current_page_classification,
     int* max_relevance) {
@@ -705,25 +713,6 @@ int OmniboxFieldTrial::GetPhysicalWebAfterTypingBaseRelevance() {
   return 700;
 }
 
-// static
-bool OmniboxFieldTrial::InZeroSuggestRedirectToChromeFieldTrial() {
-  return base::FeatureList::IsEnabled(omnibox::kZeroSuggestRedirectToChrome);
-}
-
-// static
-std::string OmniboxFieldTrial::ZeroSuggestRedirectToChromeServerAddress() {
-  return base::GetFieldTrialParamValueByFeature(
-      omnibox::kZeroSuggestRedirectToChrome,
-      kZeroSuggestRedirectToChromeServerAddressParam);
-}
-
-// static
-std::string OmniboxFieldTrial::ZeroSuggestRedirectToChromeAdditionalFields() {
-  return base::GetFieldTrialParamValueByFeature(
-      omnibox::kZeroSuggestRedirectToChrome,
-      kZeroSuggestRedirectToChromeAdditionalFieldsParam);
-}
-
 const char OmniboxFieldTrial::kBundledExperimentFieldTrialName[] =
     "OmniboxBundledExperimentV1";
 const char OmniboxFieldTrial::kDisableProvidersRule[] = "DisableProviders";
@@ -805,16 +794,13 @@ const char OmniboxFieldTrial::kPhysicalWebZeroSuggestBaseRelevanceParam[] =
 const char OmniboxFieldTrial::kPhysicalWebAfterTypingBaseRelevanceParam[] =
     "PhysicalWebAfterTypingBaseRelevanceParam";
 
-const char OmniboxFieldTrial::kZeroSuggestRedirectToChromeServerAddressParam[] =
-    "ZeroSuggestRedirectToChromeServerAddress";
-const char
-    OmniboxFieldTrial::kZeroSuggestRedirectToChromeAdditionalFieldsParam[] =
-        "ZeroSuggestRedirectToChromeAdditionalFields";
-
 const char OmniboxFieldTrial::kUIMaxAutocompleteMatchesParam[] =
     "UIMaxAutocompleteMatches";
 const char OmniboxFieldTrial::kUIVerticalMarginParam[] = "UIVerticalMargin";
 
+const char OmniboxFieldTrial::kZeroSuggestRedirectToChromeExperimentIdParam[] =
+    "ZeroSuggestRedirectToChromeExperimentID";
+
 // static
 int OmniboxFieldTrial::kDefaultMinimumTimeBetweenSuggestQueriesMs = 100;
 

components/omnibox/browser/omnibox_field_trial.h

@@ -199,6 +199,13 @@ class OmniboxFieldTrial {
   // show recently searched-for queries instead.
   static bool InZeroSuggestPersonalizedFieldTrial();
 
+  // ---------------------------------------------------------
+  // For the Zero Suggest Redirect to Chrome field trial.
+
+  // Returns the server-side experiment ID to use for contextual suggestions.
+  // Returns -1 if there is no associated experiment ID.
+  static int GetZeroSuggestRedirectToChromeExperimentId();
+
   // ---------------------------------------------------------
   // For the ShortcutsScoringMaxRelevance experiment that's part of the
   // bundled omnibox field trial.
@@ -419,26 +426,6 @@ class OmniboxFieldTrial {
   // the user has started typing in the omnibox.
   static int GetPhysicalWebAfterTypingBaseRelevance();
 
-  // ---------------------------------------------------------
-  // For experiment redirecting zero suggest requests to a service provided by
-  // the Chrome team.
-
-  // Returns true whether the user is in the field trial which redirects zero
-  // suggest requests to the service provided by the Chrome team.
-  static bool InZeroSuggestRedirectToChromeFieldTrial();
-
-  // Returns a string representing the address of the server where the zero
-  // suggest requests are being redirected. The return value is a URL
-  // (https://example.com/test) and it doesn't include any query component
-  // (no "?").
-  static std::string ZeroSuggestRedirectToChromeServerAddress();
-
-  // Returns a string representing the parameters that are sent to the
-  // alternative service providing zero suggestions. The returned value is
-  // properly escaped. It can be appended to the string representaiton of a
-  // request URL.
-  static std::string ZeroSuggestRedirectToChromeAdditionalFields();
-
   // ---------------------------------------------------------
   // Clipboard URL suggestions:
 
@@ -505,15 +492,13 @@ class OmniboxFieldTrial {
   static const char kPhysicalWebZeroSuggestBaseRelevanceParam[];
   static const char kPhysicalWebAfterTypingBaseRelevanceParam[];
 
-  // Parameter names used by the experiment redirecting Zero Suggestion requests
-  // to a service provided by the Chrome team.
-  static const char kZeroSuggestRedirectToChromeServerAddressParam[];
-  static const char kZeroSuggestRedirectToChromeAdditionalFieldsParam[];
-
   // Parameter names used by UI experiments.
   static const char kUIMaxAutocompleteMatchesParam[];
   static const char kUIVerticalMarginParam[];
 
+  // Parameter names used by Zero Suggest Redirect to Chrome.
+  static const char kZeroSuggestRedirectToChromeExperimentIdParam[];
+
   // The amount of time to wait before sending a new suggest request after the
   // previous one unless overridden by a field trial parameter.
   // Non-const because some unittests modify this value.

components/omnibox/browser/shortcuts_provider_unittest.cc

@@ -207,7 +207,6 @@ class FakeAutocompleteProviderClient
   }
 
  private:
-  base::test::ScopedTaskEnvironment scoped_task_environment_;
   base::SequencedWorkerPoolOwner pool_owner_;
   base::ScopedTempDir history_dir_;
   std::unique_ptr<history::HistoryService> history_service_;
@@ -261,6 +260,7 @@ class ShortcutsProviderTest : public testing::Test {
                      const ShortcutsDatabase::Shortcut& shortcut,
                      int max_relevance);
 
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
   std::unique_ptr<FakeAutocompleteProviderClient> client_;
   scoped_refptr<ShortcutsProvider> provider_;
 };

components/omnibox/browser/zero_suggest_provider.h

@@ -98,9 +98,6 @@ class ZeroSuggestProvider : public BaseSearchProvider,
   AutocompleteMatch NavigationToMatch(
       const SearchSuggestionParser::NavigationResult& navigation);
 
-  // Fetches zero-suggest suggestions by sending a request using |suggest_url|.
-  void Run(const GURL& suggest_url);
-
   // Converts the parsed results to a set of AutocompleteMatches and adds them
   // to |matches_|.  Also update the histograms for how many results were
   // received.
@@ -112,21 +109,22 @@ class ZeroSuggestProvider : public BaseSearchProvider,
   AutocompleteMatch MatchForCurrentURL();
 
   // When the user is in the Most Visited field trial, we ask the TopSites
-  // service for the most visited URLs during Run().  It calls back to this
-  // function to return those |urls|.
+  // service for the most visited URLs. It then calls back to this function to
+  // return those |urls|.
   void OnMostVisitedUrlsAvailable(const history::MostVisitedURLList& urls);
 
+  // When the user is in the contextual omnibox suggestions field trial, we ask
+  // the ContextualSuggestionsService for a fetcher to retrieve recommendations.
+  // When the fetcher is ready, the contextual suggestion service then calls
+  // back to this function with the |fetcher| to use for the request.
+  void OnContextualSuggestionsFetcherAvailable(
+      std::unique_ptr<net::URLFetcher> fetcher);
+
   // Whether we can show zero suggest suggestions that are not based on
   // |current_page_url|. Also checks that other conditions for non-contextual
   // zero suggest are satisfied.
   bool ShouldShowNonContextualZeroSuggest(const GURL& current_page_url) const;
 
-  // Returns a URL string that should be used to to request contextual
-  // suggestions from the default provider.  Does not take into account whether
-  // sending this request is prohibited (e.g., in an incognito window).  Returns
-  // an empty string in case of an error.
-  std::string GetContextualSuggestionsUrl() const;
-
   // Checks whether we have a set of zero suggest results cached, and if so
   // populates |matches_| with cached results.
   void MaybeUseCachedSuggestions();

ios/chrome/browser/autocomplete/autocomplete_provider_client_impl.cc

@@ -82,6 +82,11 @@ AutocompleteProviderClientImpl::GetTemplateURLService() const {
   return ios::TemplateURLServiceFactory::GetForBrowserState(browser_state_);
 }
 
+ContextualSuggestionsService*
+AutocompleteProviderClientImpl::GetContextualSuggestionsService() const {
+  return nullptr;
+}
+
 const SearchTermsData& AutocompleteProviderClientImpl::GetSearchTermsData()
     const {
   return search_terms_data_;

ios/chrome/browser/autocomplete/autocomplete_provider_client_impl.h

@@ -34,6 +34,8 @@ class AutocompleteProviderClientImpl : public AutocompleteProviderClient {
   InMemoryURLIndex* GetInMemoryURLIndex() override;
   TemplateURLService* GetTemplateURLService() override;
   const TemplateURLService* GetTemplateURLService() const override;
+  ContextualSuggestionsService* GetContextualSuggestionsService()
+      const override;
   const SearchTermsData& GetSearchTermsData() const override;
   scoped_refptr<ShortcutsBackend> GetShortcutsBackend() override;
   scoped_refptr<ShortcutsBackend> GetShortcutsBackendIfExists() override;