[AiS] Provide Answers queries with a session token.

chrome/browser/autocomplete/search_provider.cc

 // Copyright 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 "chrome/browser/autocomplete/search_provider.h"
 
 #include <algorithm>
 #include <cmath>
 
+#include "base/base64.h"
 #include "base/callback.h"
+#include "base/command_line.h"
 #include "base/i18n/break_iterator.h"
 #include "base/i18n/case_conversion.h"
 #include "base/json/json_string_value_serializer.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/prefs/pref_service.h"
+#include "base/rand_util.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/autocomplete/autocomplete_classifier.h"
 #include "chrome/browser/autocomplete/autocomplete_classifier_factory.h"
 #include "chrome/browser/autocomplete/autocomplete_provider_listener.h"
 #include "chrome/browser/autocomplete/autocomplete_result.h"
 #include "chrome/browser/autocomplete/keyword_provider.h"
 #include "chrome/browser/autocomplete/url_prefix.h"
 #include "chrome/browser/google/google_util.h"
 #include "chrome/browser/history/history_service.h"
 #include "chrome/browser/history/history_service_factory.h"
 #include "chrome/browser/history/in_memory_database.h"
 #include "chrome/browser/metrics/variations/variations_http_header_provider.h"
 #include "chrome/browser/omnibox/omnibox_field_trial.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/search/search.h"
 #include "chrome/browser/search_engines/template_url_prepopulate_data.h"
 #include "chrome/browser/search_engines/template_url_service.h"
 #include "chrome/browser/search_engines/template_url_service_factory.h"
 #include "chrome/browser/ui/search/instant_controller.h"
+#include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/common/url_constants.h"
 #include "content/public/browser/user_metrics.h"
 #include "grit/generated_resources.h"
 #include "net/base/escape.h"
 #include "net/base/load_flags.h"
 #include "net/base/net_util.h"
 #include "net/http/http_request_headers.h"
 #include "net/url_request/url_fetcher.h"
 #include "net/url_request/url_request_status.h"
@@ skipping 583 matching lines @@
     int id,
     const TemplateURL* template_url,
     const AutocompleteInput& input) {
   if (!template_url || template_url->suggestions_url().empty())
     return NULL;
 
   // Bail if the suggestion URL is invalid with the given replacements.
   TemplateURLRef::SearchTermsArgs search_term_args(input.text());
   search_term_args.cursor_position = input.cursor_position();
   search_term_args.page_classification = input.current_page_classification();
+#if defined(OS_ANDROID)
+  if (CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kEnableAnswersInSuggest))
+    search_term_args.session_token = GetSessionToken();
+#endif
   GURL suggest_url(template_url->suggestions_url_ref().ReplaceSearchTerms(
       search_term_args));
   if (!suggest_url.is_valid())
     return NULL;
   // Send the current page URL if user setting and URL requirements are met and
   // the user is in the field trial.
   if (CanSendURL(current_page_url_, suggest_url, template_url,
                  input.current_page_classification(), profile_) &&
       OmniboxFieldTrial::InZeroSuggestAfterTypingFieldTrial()) {
     search_term_args.current_page_url = current_page_url_.spec();
@@ skipping 474 matching lines @@
   match.RecordAdditionalInfo(kShouldPrefetchKey, kFalse);
 
   return match;
 }
 
 void SearchProvider::UpdateDone() {
   // We're done when the timer isn't running, there are no suggest queries
   // pending, and we're not waiting on Instant.
   done_ = !timer_.IsRunning() && (suggest_results_pending_ == 0);
 }
+
+std::string SearchProvider::GetSessionToken() {
+  base::TimeTicks current_time(base::TimeTicks::Now());
+  // Renew token if it expired.
+  if (current_time > token_expiration_time_) {
+    const size_t kTokenBytes = 12;
+    std::string raw_data;
+    base::RandBytes(WriteInto(&raw_data, kTokenBytes + 1), kTokenBytes);
+    base::Base64Encode(raw_data, &current_token_);
+  }
+
+  // Extend expiration time another 60 seconds.
+  token_expiration_time_ = current_time + base::TimeDelta::FromSeconds(60);
+
+  return current_token_;
+}