Add ContextualSuggestionsService to Omnibox

components/contextual_suggestions/contextual_suggestions_service.cc

Index: components/contextual_suggestions/contextual_suggestions_service.cc
diff --git a/components/contextual_suggestions/contextual_suggestions_service.cc b/components/contextual_suggestions/contextual_suggestions_service.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3fe9858a0d1838f55010b1076b06028cd58867e9
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+++ b/components/contextual_suggestions/contextual_suggestions_service.cc
@@ -0,0 +1,188 @@
+// 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 "components/contextual_suggestions/contextual_suggestions_service.h"
+
+#include "base/memory/ptr_util.h"
+#include "base/metrics/field_trial_params.h"
+#include "components/data_use_measurement/core/data_use_user_data.h"
+#include "components/variations/net/variations_http_headers.h"
+#include "google_apis/gaia/gaia_constants.h"
+#include "net/base/escape.h"
+#include "net/base/load_flags.h"
+#include "net/http/http_response_headers.h"
+#include "net/traffic_annotation/network_traffic_annotation.h"
+#include "net/url_request/url_fetcher.h"
+
+namespace contextual_suggestions {
+
+namespace {
+
+// Parameter names used by the experiment redirecting Zero Suggestion requests
+// to a service provided by the Chrome team
+const char kZeroSuggestRedirectToChromeServerAddressParam[] =
+    "ZeroSuggestRedirectToChromeServerAddress";
+const char kZeroSuggestRedirectToChromeAdditionalFieldsParam[] =
+    "ZeroSuggestRedirectToChromeAdditionalFields";
+
+// Format string for OAuth2 authentication headers.
+const char kAuthorizationHeaderFormat[] = "Authorization: Bearer %s";
+
+}  // namespace
+
+const base::Feature kZeroSuggestRedirectToChrome{
+    "ZeroSuggestRedirectToChrome", base::FEATURE_DISABLED_BY_DEFAULT};
+
+ContextualSuggestionsService::ContextualSuggestionsService(
+    SigninManagerBase* signin_manager,
+    OAuth2TokenService* token_service,
+    TemplateURLService* template_url_service,
+    net::URLRequestContextGetter* request_context)
+    : signin_manager_(signin_manager),
+      token_service_(token_service),
+      template_url_service_(template_url_service),
+      request_context_(request_context) {}
+
+ContextualSuggestionsService::~ContextualSuggestionsService() {}
+
+bool ContextualSuggestionsService::UseExperimentalZeroSuggestSuggestions()
+    const {
+  if (!base::FeatureList::IsEnabled(kZeroSuggestRedirectToChrome) ||
+      template_url_service_ == nullptr)
+    return false;

[Marc Treib, 2017/07/06 08:32:20]

nit: add braces if the condition doesn't fit on one line

[gcomanici, 2017/07/06 15:34:17]

Done.

+
+  // Check that the default search engine is Google.
+  const TemplateURL& default_provider_url =
+      *template_url_service_->GetDefaultSearchProvider();
+  const SearchTermsData& search_terms_data =
+      template_url_service_->search_terms_data();
+  if (default_provider_url.GetEngineType(search_terms_data) !=
+      SEARCH_ENGINE_GOOGLE)
+    return false;

[Marc Treib, 2017/07/06 08:32:20]

Here too

[gcomanici, 2017/07/06 15:34:17]

Done.

+
+  // Check that the suggest URL for redirect to chrome field trial is valid.
+  const GURL suggest_url =
+      ExperimentalZeroSuggestURL(/*visited_url=*/std::string());
+  if (!suggest_url.is_valid())
+    return false;
+
+  // Check that the suggest URL for redirect to chrome is HTTPS.
+  return suggest_url.SchemeIsCryptographic();
+}
+
+bool ContextualSuggestionsService::CreateContextualSuggestionsRequest(
+    const std::string& visited_url,
+    net::URLFetcherDelegate* fetcher_delegate,
+    ContextualSuggestionsCallback callback) {
+  DCHECK(signin_manager_);
+  DCHECK(token_service_);
+
+  // Skip this request is still waiting for oauth2 token.

[Marc Treib, 2017/07/06 08:32:20]

s/is/if/ ?

[gcomanici, 2017/07/06 15:34:17]

Done.

+  if (token_fetcher_)
+    return false;
+
+  std::unique_ptr<net::URLFetcher> fetcher =
+      CreateRequest(visited_url, fetcher_delegate);
+  if (fetcher == nullptr)
+    return false;
+
+  // Create the oauth2 token fetcher.
+  OAuth2TokenService::ScopeSet scopes{GaiaConstants::kAnyApiOAuth2Scope};
+  token_fetcher_ = base::MakeUnique<AccessTokenFetcher>(
+      "contextual_suggestions_service", signin_manager_, token_service_, scopes,
+      base::BindOnce(&ContextualSuggestionsService::AccessTokenAvailable,
+                     base::Unretained(this), std::move(fetcher),
+                     std::move(callback)));
+  return true;
+}
+
+// static
+GURL ContextualSuggestionsService::ExperimentalZeroSuggestURL(
+    const std::string visited_url) {
+  const std::string server_address = base::GetFieldTrialParamValueByFeature(
+      kZeroSuggestRedirectToChrome,
+      kZeroSuggestRedirectToChromeServerAddressParam);
+  const std::string additional_parameters =
+      base::GetFieldTrialParamValueByFeature(
+          kZeroSuggestRedirectToChrome,
+          kZeroSuggestRedirectToChromeAdditionalFieldsParam);
+  return GURL(server_adddress + "/url=" + net::EscapePath(visited_url) +
+              additional_parameters);
+}
+
+std::unique_ptr<net::URLFetcher> ContextualSuggestionsService::CreateRequest(
+    const std::string& visited_url,
+    net::URLFetcherDelegate* fetcher_delegate) {
+  net::NetworkTrafficAnnotationTag traffic_annotation =
+      net::DefineNetworkTrafficAnnotation("omnibox_contextual_zerosuggest", R"(
+        semantics {
+          sender: "Omnibox"
+          description:
+            "When the user focuses the omnibox, Chrome can provide search or "
+            "navigation suggestions from the default search provider in the "
+            "omnibox dropdown, based on the current page URL.\n"
+            "This is limited to users whose default search engine is Google, "
+            "as no other search engines currently support this kind of "
+            "suggestion."
+          trigger: "The omnibox receives focus."
+          data: "The URL of the current page."
+          destination: GOOGLE_OWNED_SERVICE
+        }
+        policy {
+          cookies_allowed: true

[Marc Treib, 2017/07/06 08:32:20]

Does this actually require cookies? If you're doing OAuth2 authentication, then
presumably cookies aren't necessary?

[gcomanici, 2017/07/06 15:34:17]

Good point. I was using the same annotation tag as before, but indeed cookies
are no longer needed.

[Marc Treib, 2017/07/06 16:02:45]

Ah, but then you also need to set net::LOAD_DO_NOT_SEND_COOKIES below.

[gcomanici, 2017/07/06 16:54:16]

Done.

+          cookies_store: "user"
+          setting:
+            "Users can control this feature via the 'Use a prediction service "
+            "to help complete searches and URLs typed in the address bar' "
+            "settings under 'Privacy'. The feature is enabled by default."
+          chrome_policy {
+            SearchSuggestEnabled {
+                policy_options {mode: MANDATORY}
+                SearchSuggestEnabled: false
+            }
+          }
+        })");
+  const int kFetcherID = 1;
+  const GURL suggest_url = ExperimentalZeroSuggestURL(visited_url);
+  if (!suggest_url.is_valid())

[Marc Treib, 2017/07/06 08:32:20]

If this were the case, we shouldn't get here, right? If so, maybe just DCHECK
that the URL is valid?

[gcomanici, 2017/07/06 15:34:18]

Added a DCHECK.

[Marc Treib, 2017/07/06 16:02:45]

It's the wrong way around though ;)

[gcomanici, 2017/07/06 16:54:16]

Fixed :)

+    return nullptr;
+
+  std::unique_ptr<net::URLFetcher> fetcher =
+      net::URLFetcher::Create(kFetcherID, suggest_url, net::URLFetcher::GET,
+                              fetcher_delegate, traffic_annotation);
+  data_use_measurement::DataUseUserData::AttachToFetcher(
+      fetcher.get(), data_use_measurement::DataUseUserData::OMNIBOX);
+  fetcher->SetRequestContext(request_context_);
+  fetcher->SetLoadFlags(net::LOAD_DO_NOT_SAVE_COOKIES);
+  // Add Chrome experiment state to the request headers.
+  net::HttpRequestHeaders headers;
+  // Note: It's OK to pass |is_signed_in| false if it's unknown, as it does
+  // not affect transmission of experiments coming from the variations server.
+  variations::AppendVariationHeaders(fetcher->GetOriginalURL(),
+                                     /*incognito=*/false,
+                                     /*uma_enabled=*/false,
+                                     /*is_signed_in=*/false, &headers);
+  fetcher->SetExtraRequestHeaders(headers.ToString());
+  return fetcher;
+}
+
+void ContextualSuggestionsService::AccessTokenAvailable(
+    std::unique_ptr<net::URLFetcher> fetcher,
+    ContextualSuggestionsCallback callback,
+    const GoogleServiceAuthError& error,
+    const std::string& access_token) {
+  DCHECK(token_fetcher_);
+  std::unique_ptr<AccessTokenFetcher> token_fetcher_deleter(
+      std::move(token_fetcher_));
+
+  if (error.state() != GoogleServiceAuthError::NONE) {
+    return;
+  }

[Marc Treib, 2017/07/06 08:32:20]

nit: Other places in this file don't use braces for single-line bodies

[gcomanici, 2017/07/06 15:34:17]

I chanced the other places for consistency.

+  DCHECK(!access_token.empty());
+  fetcher->AddExtraRequestHeader(
+      base::StringPrintf(kAuthorizationHeaderFormat, access_token.c_str()));
+  std::move(callback).Run(std::move(fetcher));

[Marc Treib, 2017/07/06 08:32:20]

Is it okay to just not call the callback if something went wrong? If that's the
contract this service provides, then IMO that should be called out in a comment
in the header.
(It looks like the omnibox code expects to be called back with nullptr though?)

[gcomanici, 2017/07/06 15:34:17]

I changed the description and signature for CreateContextualSuggestionsRequest.
Indeed the callback is called synchronously either when an error is encountered
(with nullptr) or after the fetcher is properly built.

+}
+
+}  // namespace contextual_suggestions