Re-enable SystemMonitor.* in base_unittests.

base/system_monitor_unittest.cc

 // Copyright (c) 2008 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 "base/system_monitor.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 class PowerTest : public base::SystemMonitor::PowerObserver {
  public:
   PowerTest()
@@ skipping 13 matching lines @@
   int suspends() { return suspends_; }
   int resumes() { return resumes_; }
 
  private:
   bool battery_;   // Do we currently think we're on battery power.
   int power_state_changes_;  // Count of OnPowerStateChange notifications.
   int suspends_;  // Count of OnSuspend notifications.
   int resumes_;  // Count of OnResume notifications.
 };
 
-// Disabled as a temporary workaround for http://crbug.com/12187
-TEST(SystemMonitor, DISABLED_PowerNotifications) {
+TEST(SystemMonitor, PowerNotifications) {
   const int kObservers = 5;
 
   // Initialize a message loop for this to run on.
   MessageLoop loop;
   // Initialize time() since it registers as a SystemMonitor observer.
   base::Time now = base::Time::Now();
 
   base::SystemMonitor* monitor = base::SystemMonitor::Get();
   PowerTest test[kObservers];
   for (int index = 0; index < kObservers; ++index)
@@ skipping 24 matching lines @@
   // Pretend we were awakened.
   monitor->ProcessPowerMessage(base::SystemMonitor::RESUME_EVENT);
   loop.RunAllPending();
   EXPECT_EQ(test[0].resumes(), 1);
 
   // Send a duplicate resume notification.  This should be suppressed.
   monitor->ProcessPowerMessage(base::SystemMonitor::RESUME_EVENT);
   loop.RunAllPending();
   EXPECT_EQ(test[0].resumes(), 1);
 }