Expose a method in VariationsService to trigger a seed fetch.

chrome/browser/metrics/variations/variations_request_scheduler_mobile_unittest.cc

+// Copyright 2013 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_request_scheduler_mobile.h"
+
+#include "base/bind.h"
+#include "base/prefs/pref_registry_simple.h"
+#include "base/prefs/testing_pref_service.h"
+#include "chrome/common/pref_names.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace chrome_variations {
+
+namespace {
+
+// Simple method used to verify a Callback has been triggered.
+void SetToOne(int *n) {
+  *n = 1;
+}
+
+}  // namespace
+
+TEST(VariationsRequestSchedulerMobileTest, StartNoRun) {
+  TestingPrefServiceSimple prefs;
+  // Initialize to as if it was just fetched.
+  prefs.registry()->RegisterInt64Pref(
+      prefs::kVariationsLastFetchTime, base::Time::Now().ToInternalValue());
+  int executed = 0;
+  const base::Closure task = base::Bind(&SetToOne, &executed);
+  VariationsRequestSchedulerMobile scheduler(task, &prefs);
+  scheduler.Start();
+  // We expect it the task to not have triggered.
+  EXPECT_EQ(0, executed);
+}
+
+TEST(VariationsRequestSchedulerMobileTest, StartRun) {
+  TestingPrefServiceSimple prefs;
+  // Verify it doesn't take more than a day.
+  base::Time old = base::Time::Now() - base::TimeDelta::FromHours(24);
+  prefs.registry()->RegisterInt64Pref(
+      prefs::kVariationsLastFetchTime, old.ToInternalValue());
+  int executed = 0;
+  const base::Closure task = base::Bind(&SetToOne, &executed);
+  VariationsRequestSchedulerMobile scheduler(task, &prefs);
+  scheduler.Start();
+  // We expect the task to have triggered.
+  EXPECT_EQ(1, executed);
+}
+
+}  // namespace chrome_variations