Initialize variations seed fetching via OnAppEnterForeground.

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/build_time.h"
 #include "base/command_line.h"
@@ skipping 333 matching lines @@
 }
 
 void VariationsService::AddObserver(Observer* observer) {
   observer_list_.AddObserver(observer);
 }
 
 void VariationsService::RemoveObserver(Observer* observer) {
   observer_list_.RemoveObserver(observer);
 }
 
-// TODO(rkaplow): Handle this and the similar event in metrics_service by
-// observing an 'OnAppEnterForeground' event in RequestScheduler instead of
-// requiring the frontend code to notify each service individually. Since the
-// scheduler will handle it directly the VariationService shouldn't need to
-// know details of this anymore.
 void VariationsService::OnAppEnterForeground() {
+  // On mobile platforms, initialize the fetch scheduler when we receive the
+  // first app foreground notification.
+  if (!request_scheduler_)
+    StartRepeatedVariationsSeedFetch();
   request_scheduler_->OnAppEnterForeground();
 }
 
 #if defined(OS_WIN)
 void VariationsService::StartGoogleUpdateRegistrySync() {
   registry_syncer_.RequestRegistrySync();
 }
 #endif
 
 void VariationsService::SetRestrictMode(const std::string& restrict_mode) {
@@ skipping 275 matching lines @@
     local_state_->SetInt64(prefs::kVariationsLastFetchTime,
                            base::Time::Now().ToInternalValue());
   }
 }
 
 std::string VariationsService::GetInvalidVariationsSeedSignature() const {
   return seed_store_.GetInvalidSignature();
 }
 
 }  // namespace chrome_variations