Replace Chrome IPC with Mojo IPC for querying BatteryStatus service

content/browser/battery_status/battery_status_manager_win.cc

-// Copyright 2014 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 "content/browser/battery_status/battery_status_manager_win.h"
-
-#include "base/memory/ref_counted.h"
-#include "base/metrics/histogram.h"
-#include "base/strings/string16.h"
-#include "base/win/message_window.h"
-#include "base/win/windows_version.h"
-#include "content/browser/battery_status/battery_status_manager.h"
-#include "content/public/browser/browser_thread.h"
-
-namespace content {
-
-namespace {
-
-typedef BatteryStatusService::BatteryUpdateCallback BatteryCallback;
-
-const wchar_t kWindowClassName[] = L"BatteryStatusMessageWindow";
-
-// This enum is used for histogram. Don't change the order of the existing
-// values.
-enum NumberBatteriesType {
-  UNKNOWN_BATTERIES = 0,
-  NO_BATTERY = 1,
-  ONE_OR_MORE_BATTERIES = 2,
-  BATTERY_TYPES_COUNT = 3,
-};
-
-void UpdateNumberBatteriesHistogram(NumberBatteriesType count) {
-  UMA_HISTOGRAM_ENUMERATION("BatteryStatus.NumberBatteriesWin",
-                            count,
-                            BATTERY_TYPES_COUNT);
-}
-
-void UpdateNumberBatteriesHistogram() {
-  SYSTEM_POWER_STATUS win_status;
-  if (!GetSystemPowerStatus(&win_status)) {
-    UpdateNumberBatteriesHistogram(UNKNOWN_BATTERIES);
-    return;
-  }
-
-  if (win_status.BatteryFlag == 255)
-    UpdateNumberBatteriesHistogram(UNKNOWN_BATTERIES);
-  else if (win_status.BatteryFlag == 128)
-    UpdateNumberBatteriesHistogram(NO_BATTERY);
-  else
-    UpdateNumberBatteriesHistogram(ONE_OR_MORE_BATTERIES);
-}
-
-// Message-only window for handling battery changes on Windows.
-class BatteryStatusObserver
-    : public base::RefCountedThreadSafe<BatteryStatusObserver> {
- public:
-  explicit BatteryStatusObserver(const BatteryCallback& callback)
-      : power_handle_(NULL),
-        battery_change_handle_(NULL),
-        callback_(callback) {
-  }
-
-  virtual ~BatteryStatusObserver() { DCHECK(!window_); }
-
-  void Start() {
-    // Need to start on the UI thread to receive battery status notifications.
-    BrowserThread::PostTask(
-        BrowserThread::UI,
-        FROM_HERE,
-        base::Bind(&BatteryStatusObserver::StartOnUI, this));
-  }
-
-  void Stop() {
-    BrowserThread::PostTask(
-        BrowserThread::UI,
-        FROM_HERE,
-        base::Bind(&BatteryStatusObserver::StopOnUI, this));
-  }
-
- private:
-  void StartOnUI() {
-    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-    if (window_)
-      return;
-
-    if (CreateMessageWindow()) {
-      BatteryChanged();
-      // RegisterPowerSettingNotification function work from Windows Vista
-      // onwards. However even without them we will receive notifications,
-      // e.g. when a power source is connected.
-      // TODO(timvolodine) : consider polling for battery changes on windows
-      // versions prior to Vista, see crbug.com/402466.
-      power_handle_ =
-          RegisterNotification(&GUID_ACDC_POWER_SOURCE);
-      battery_change_handle_ =
-          RegisterNotification(&GUID_BATTERY_PERCENTAGE_REMAINING);
-    } else {
-      // Could not create a message window, execute callback with the default
-      // values.
-      callback_.Run(blink::WebBatteryStatus());
-    }
-
-    UpdateNumberBatteriesHistogram();
-  }
-
-  void StopOnUI() {
-    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-    if (!window_)
-      return;
-
-    if (power_handle_)
-      UnregisterNotification(power_handle_);
-    if (battery_change_handle_)
-      UnregisterNotification(battery_change_handle_);
-    window_.reset();
-  }
-
-  void BatteryChanged() {
-    SYSTEM_POWER_STATUS win_status;
-    if (GetSystemPowerStatus(&win_status))
-      callback_.Run(ComputeWebBatteryStatus(win_status));
-    else
-      callback_.Run(blink::WebBatteryStatus());
-  }
-
-  bool HandleMessage(UINT message,
-                     WPARAM wparam,
-                     LPARAM lparam,
-                     LRESULT* result) {
-    switch(message) {
-      case WM_POWERBROADCAST:
-        if (wparam == PBT_APMPOWERSTATUSCHANGE ||
-            wparam == PBT_POWERSETTINGCHANGE) {
-          BatteryChanged();
-        }
-        *result = NULL;
-        return true;
-      default:
-        return false;
-    }
-  }
-
-  HPOWERNOTIFY RegisterNotification(LPCGUID power_setting) {
-    if (base::win::GetVersion() < base::win::VERSION_VISTA)
-      return NULL;
-
-    return RegisterPowerSettingNotification(window_->hwnd(), power_setting,
-                                     DEVICE_NOTIFY_WINDOW_HANDLE);
-  }
-
-  BOOL UnregisterNotification(HPOWERNOTIFY handle) {
-    if (base::win::GetVersion() < base::win::VERSION_VISTA)
-      return FALSE;
-
-    return UnregisterPowerSettingNotification(handle);
-  }
-
-  bool CreateMessageWindow() {
-    // TODO(timvolodine): consider reusing the message window of PowerMonitor.
-    window_.reset(new base::win::MessageWindow());
-    if (!window_->CreateNamed(base::Bind(&BatteryStatusObserver::HandleMessage,
-                                         base::Unretained(this)),
-                              base::string16(kWindowClassName))) {
-      LOG(ERROR) << "Failed to create message window: " << kWindowClassName;
-      window_.reset();
-      return false;
-    }
-    return true;
-  }
-
-  HPOWERNOTIFY power_handle_;
-  HPOWERNOTIFY battery_change_handle_;
-  BatteryCallback callback_;
-  scoped_ptr<base::win::MessageWindow> window_;
-
-  DISALLOW_COPY_AND_ASSIGN(BatteryStatusObserver);
-};
-
-class BatteryStatusManagerWin : public BatteryStatusManager {
- public:
-  explicit BatteryStatusManagerWin(const BatteryCallback& callback)
-      : battery_observer_(new BatteryStatusObserver(callback)) {}
-  virtual ~BatteryStatusManagerWin() { battery_observer_->Stop(); }
-
- public:
-  // BatteryStatusManager:
-  virtual bool StartListeningBatteryChange() override {
-    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-    battery_observer_->Start();
-    return true;
-  }
-
-  virtual void StopListeningBatteryChange() override {
-    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-    battery_observer_->Stop();
-  }
-
- private:
-  scoped_refptr<BatteryStatusObserver> battery_observer_;
-
-  DISALLOW_COPY_AND_ASSIGN(BatteryStatusManagerWin);
-};
-
-}  // namespace
-
-blink::WebBatteryStatus ComputeWebBatteryStatus(
-    const SYSTEM_POWER_STATUS& win_status) {
-  blink::WebBatteryStatus status;
-  status.charging = win_status.ACLineStatus != WIN_AC_LINE_STATUS_OFFLINE;
-
-  // Set level if available. Otherwise keep the default value which is 1.
-  if (win_status.BatteryLifePercent != 255) {
-    // Convert percentage to a value between 0 and 1 with 2 significant digits.
-    status.level = static_cast<double>(win_status.BatteryLifePercent) / 100.;
-  }
-
-  if (!status.charging) {
-    // Set dischargingTime if available otherwise keep the default value,
-    // which is +Infinity.
-    if (win_status.BatteryLifeTime != (DWORD)-1)
-      status.dischargingTime = win_status.BatteryLifeTime;
-    status.chargingTime = std::numeric_limits<double>::infinity();
-  } else {
-    // Set chargingTime to +Infinity if not fully charged, otherwise leave the
-    // default value, which is 0.
-    if (status.level < 1)
-      status.chargingTime = std::numeric_limits<double>::infinity();
-  }
-  return status;
-}
-
-// static
-scoped_ptr<BatteryStatusManager> BatteryStatusManager::Create(
-    const BatteryStatusService::BatteryUpdateCallback& callback) {
-  return scoped_ptr<BatteryStatusManager>(
-      new BatteryStatusManagerWin(callback));
-}
-
-}  // namespace content