Activate the VariationsService for ChromeOS and ensure that it does not ping the server until the E…

chrome/browser/metrics/variations/variations_service.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 "chrome/browser/metrics/variations/variations_service.h"
 
 #include <set>
 
 #include "base/base64.h"
 #include "base/build_time.h"
 #include "base/command_line.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/metrics/field_trial.h"
-#include "base/metrics/histogram.h"
 #include "base/version.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/metrics/proto/trials_seed.pb.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/metrics/variations/variations_util.h"
 #include "chrome/common/pref_names.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/common/url_fetcher.h"
 #include "googleurl/src/gurl.h"
@@ skipping 66 matching lines @@
   if (server_url.empty())
     server_url = kDefaultVariationsServerURL;
   GURL url_as_gurl = GURL(server_url);
   DCHECK(url_as_gurl.is_valid());
   return url_as_gurl;
 }
 
 }  // namespace
 
 VariationsService::VariationsService()
-    : variations_server_url_(GetVariationsServerURL()),
-      create_trials_from_seed_called_(false),
-      was_offline_during_last_request_attempt_(false) {
-  net::NetworkChangeNotifier::AddConnectionTypeObserver(this);
+    : create_trials_from_seed_called_(false),
+      variations_server_url_(GetVariationsServerURL()),
+      resource_request_allowed_notifier_(new ResourceRequestAllowedNotifier) {
+  resource_request_allowed_notifier_->SetObserver(this);
 }
 
 VariationsService::~VariationsService() {
-  net::NetworkChangeNotifier::RemoveConnectionTypeObserver(this);
+  resource_request_allowed_notifier_->ClearObserver();
 }
 
 bool VariationsService::CreateTrialsFromSeed(PrefService* local_prefs) {
   create_trials_from_seed_called_ = true;
 
   TrialsSeed seed;
   if (!LoadTrialsSeedFromPref(local_prefs, &seed))
     return false;
 
   const int64 date_value = local_prefs->GetInt64(prefs::kVariationsSeedDate);
@@ skipping 28 matching lines @@
   FetchVariationsSeed();
 
   // Repeat this periodically.
   timer_.Start(FROM_HERE, base::TimeDelta::FromHours(kSeedFetchPeriodHours),
                this, &VariationsService::FetchVariationsSeed);
 }
 
 void VariationsService::FetchVariationsSeed() {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
 
-  was_offline_during_last_request_attempt_ =
-      net::NetworkChangeNotifier::IsOffline();
-  UMA_HISTOGRAM_BOOLEAN("Variations.NetworkAvailability",
-                        !was_offline_during_last_request_attempt_);
-  if (was_offline_during_last_request_attempt_) {
-    DVLOG(1) << "Network was offline.";
+  if (!resource_request_allowed_notifier_->ResourceRequestsAllowed()) {
+    DVLOG(1) << "Resource requests were not allowed. Waiting for notification.";
     return;
   }
 
+  DoActualFetch();
+}
+
+// static
+void VariationsService::RegisterPrefs(PrefService* prefs) {
+  prefs->RegisterStringPref(prefs::kVariationsSeed, std::string());
+  prefs->RegisterInt64Pref(prefs::kVariationsSeedDate,
+                           base::Time().ToInternalValue());
+}
+
+void VariationsService::DoActualFetch() {
   pending_seed_request_.reset(net::URLFetcher::Create(
       variations_server_url_, net::URLFetcher::GET, this));
   pending_seed_request_->SetLoadFlags(net::LOAD_DO_NOT_SEND_COOKIES |
                                       net::LOAD_DO_NOT_SAVE_COOKIES);
   pending_seed_request_->SetRequestContext(
       g_browser_process->system_request_context());
   pending_seed_request_->SetMaxRetries(kMaxRetrySeedFetch);
   if (!variations_serial_number_.empty()) {
     pending_seed_request_->AddExtraRequestHeader("If-Match:" +
                                                  variations_serial_number_);
   }
   pending_seed_request_->Start();
 }
 
-void VariationsService::SetWasOfflineDuringLastRequestAttemptForTesting(
-    bool offline) {
-  was_offline_during_last_request_attempt_ = offline;
-}
-
-// static
-void VariationsService::RegisterPrefs(PrefService* prefs) {
-  prefs->RegisterStringPref(prefs::kVariationsSeed, std::string());
-  prefs->RegisterInt64Pref(prefs::kVariationsSeedDate,
-                           base::Time().ToInternalValue());
+void VariationsService::SetResourceRequestAllowedNotifierForTesting(
+    ResourceRequestAllowedNotifier* notifier) {
+  DCHECK(notifier);
+  resource_request_allowed_notifier_->ClearObserver();

[Alexei Svitkine (slow), 2012/09/19 19:44:28]

The destructor of the notifier should do the sane thing and clear its own
observer. Then the call to ClearObserver() here won't be necessary since it
would be handled by the .reset() below and similarly the ClearObserver() call in
~VariationsService() could also be removed.

[SteveT, 2012/09/20 19:40:18]

This is no longer applicable.

+  resource_request_allowed_notifier_.reset(notifier);
+  notifier->SetObserver(this);
 }
 
 void VariationsService::OnURLFetchComplete(const net::URLFetcher* source) {
   DCHECK_EQ(pending_seed_request_.get(), source);
   // The fetcher will be deleted when the request is handled.
   scoped_ptr<const net::URLFetcher> request(
       pending_seed_request_.release());
   if (request->GetStatus().status() != net::URLRequestStatus::SUCCESS) {
     DVLOG(1) << "Variations server request failed.";
     return;
   }
 
   if (request->GetResponseCode() != 200) {
     DVLOG(1) << "Variations server request returned non-200 response code: "
              << request->GetResponseCode();
     return;
   }
 
   std::string seed_data;
   bool success = request->GetResponseAsString(&seed_data);
   DCHECK(success);
 
   base::Time response_date;
   success = request->GetResponseHeaders()->GetDateValue(&response_date);
   DCHECK(success || response_date.is_null());
 
   StoreSeedData(seed_data, response_date, g_browser_process->local_state());
 }
 
-void VariationsService::OnConnectionTypeChanged(
-    net::NetworkChangeNotifier::ConnectionType type) {
-  // If the connection type is back online, start a request if the last request
-  // failed due to being offline.
-  if (was_offline_during_last_request_attempt_ &&
-      type != net::NetworkChangeNotifier::CONNECTION_NONE) {
-    VLOG(1) << "Retrying fetch due to network reconnect.";
-    FetchVariationsSeed();
-
-    // Since FetchVariationsSeed was explicitly called here, reset the timer to
-    // avoid retrying for a full period.
-    // net::NetworkChangeNotifier::IsOffline may be inconsistent with |type|, so
-    // we check if FetchVariationsSeed set
-    // |was_offline_during_last_request_attempt_| to true before we reset the
-    // timer.
-    if (!was_offline_during_last_request_attempt_ && timer_.IsRunning())
-      timer_.Reset();
-  }
+void VariationsService::OnResourceRequestsAllowed() {
+  // Note that this only attempts to fetch the seed at most once per period
+  // (kSeedFetchPeriodHours). This works because
+  // |resource_request_allowed_notifier_| only calls this method if an
+  // attempt was made earlier that fails (which implies that the period had
+  // elapsed). After a successful attempt is made, the notifier will know not
+  // to call this method again until another failed attempt occurs.
+  DVLOG(1) << "Retrying fetch.";
+  FetchVariationsSeed();
+  if (timer_.IsRunning())
+    timer_.Reset();
 }
 
 bool VariationsService::StoreSeedData(const std::string& seed_data,
                                       const base::Time& seed_date,
                                       PrefService* local_prefs) {
   // Only store the seed data if it parses correctly.
   TrialsSeed seed;
   if (!seed.ParseFromString(seed_data)) {
     VLOG(1) << "Variations Seed data from server is not in valid proto format, "
             << "rejecting the seed.";
@@ skipping 248 matching lines @@
                                       variation_id);
     }
   }
 
   trial->SetForced();
   if (IsStudyExpired(study, reference_date))
     trial->Disable();
 }
 
 }  // namespace chrome_variations