base: Fix minor warnings reported by cppcheck.

base/system_monitor/system_monitor_unittest.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 "base/system_monitor/system_monitor.h"
 
 #include "base/file_path.h"
 #include "base/message_loop.h"
 #include "base/test/mock_devices_changed_observer.h"
 #include "base/utf_string_conversions.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace base {
 
 namespace {
 
 class PowerTest : public SystemMonitor::PowerObserver {
  public:
   PowerTest()
-      : battery_(false),
-        power_state_changes_(0),
+      : power_state_changes_(0),
         suspends_(0),
         resumes_(0) {
   }
 
   // PowerObserver callbacks.
   virtual void OnPowerStateChange(bool on_battery_power) OVERRIDE {
     power_state_changes_++;
   }
 
   virtual void OnSuspend() OVERRIDE {
     suspends_++;
   }
 
   virtual void OnResume() OVERRIDE {
     resumes_++;
   }
 
   // Test status counts.
-  bool battery() { return battery_; }
   int power_state_changes() { return power_state_changes_; }
   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.
 };
 
 class SystemMonitorTest : public testing::Test {
  protected:
   SystemMonitorTest() {
 #if defined(OS_MACOSX)
     // This needs to happen before SystemMonitor's ctor.
@@ skipping 148 matching lines @@
 
   system_monitor_->ProcessMediaDeviceDetached(kDeviceId2);
   message_loop_.RunAllPending();
   devices = system_monitor_->GetAttachedMediaDevices();
   EXPECT_EQ(0U, devices.size());
 }
 
 }  // namespace
 
 }  // namespace base