Move power event handling logic from ui/ to base/ on Windows

base/system_monitor/system_monitor.cc

Index: base/system_monitor/system_monitor.cc
diff --git a/base/system_monitor/system_monitor.cc b/base/system_monitor/system_monitor.cc
index 7c960cc09ff17bfec38301418de567790c6bd009..8d285efda011c22cc99506328fa57a43bcbf516d 100644
--- a/base/system_monitor/system_monitor.cc
+++ b/base/system_monitor/system_monitor.cc
@@ -10,6 +10,10 @@
 #include "base/message_loop.h"
 #include "base/time.h"
 
+#if defined(OS_WIN)
+#include "base/win/wrapped_window_proc.h"
+#endif
+
 namespace base {
 
 static SystemMonitor* g_system_monitor = NULL;
@@ -20,6 +24,116 @@ static SystemMonitor* g_system_monitor = NULL;
 static int kDelayedBatteryCheckMs = 10 * 1000;
 #endif  // defined(ENABLE_BATTERY_MONITORING)
 
+#if defined(OS_WIN)
+namespace {
+
+const wchar_t kWindowClassName[] = L"Base_PowerMessageWindow";
+
+}  // namespace
+
+class SystemMonitor::PowerMessageWindow {
+ public:
+  PowerMessageWindow();
+  ~PowerMessageWindow();
+
+ private:
+  void ProcessWmPowerBroadcastMessage(int event_id);
+  LRESULT CALLBACK WndProc(HWND hwnd, UINT message,
+                           WPARAM wparam, LPARAM lparam);
+  static LRESULT CALLBACK WndProcThunk(HWND hwnd,
+                                       UINT message,
+                                       WPARAM wparam,
+                                       LPARAM lparam);
+  // Instance of the module containing the window procedure.
+  HMODULE instance_;
+  // A hidden window handle.
+  HWND message_hwnd_;
+};
+
+SystemMonitor::PowerMessageWindow::PowerMessageWindow()
+    : instance_(NULL), message_hwnd_(NULL) {
+  WNDCLASSEX window_class;
+  base::win::InitializeWindowClass(
+      kWindowClassName,
+      &base::win::WrappedWindowProc<
+          SystemMonitor::PowerMessageWindow::WndProcThunk>,
+      0, 0, 0, NULL, NULL, NULL, NULL, NULL,
+      &window_class);
+  instance_ = window_class.hInstance;
+  ATOM clazz = RegisterClassEx(&window_class);
+  DCHECK(clazz);
+
+  message_hwnd_ = CreateWindow(kWindowClassName,
+                         NULL, 0, 0, 0, 0, 0, 0, 0, instance_, 0);
+  SetWindowLongPtr(message_hwnd_, GWLP_USERDATA,
+                   reinterpret_cast<LONG_PTR>(this));
+}
+
+SystemMonitor::PowerMessageWindow::~PowerMessageWindow() {
+  if (message_hwnd_) {
+    DestroyWindow(message_hwnd_);
+    UnregisterClass(kWindowClassName, instance_);
+  }
+}
+
+void SystemMonitor::PowerMessageWindow::ProcessWmPowerBroadcastMessage(
+    int event_id) {
+  SystemMonitor::PowerEvent power_event;
+  switch (event_id) {
+    case PBT_APMPOWERSTATUSCHANGE:  // The power status changed.
+      power_event = SystemMonitor::POWER_STATE_EVENT;
+      break;
+    case PBT_APMRESUMEAUTOMATIC:  // Resume from suspend.
+    //case PBT_APMRESUMESUSPEND:  // User-initiated resume from suspend.
+                                  // We don't notify for this latter event
+                                  // because if it occurs it is always sent as a
+                                  // second event after PBT_APMRESUMEAUTOMATIC.
+      power_event = SystemMonitor::RESUME_EVENT;
+      break;
+    case PBT_APMSUSPEND:  // System has been suspended.
+      power_event = SystemMonitor::SUSPEND_EVENT;
+      break;
+    default:
+      return;
+
+    // Other Power Events:
+    // PBT_APMBATTERYLOW - removed in Vista.
+    // PBT_APMOEMEVENT - removed in Vista.
+    // PBT_APMQUERYSUSPEND - removed in Vista.
+    // PBT_APMQUERYSUSPENDFAILED - removed in Vista.
+    // PBT_APMRESUMECRITICAL - removed in Vista.
+    // PBT_POWERSETTINGCHANGE - user changed the power settings.
+  }
+  SystemMonitor::Get()->ProcessPowerMessage(power_event);
+}
+
+LRESULT CALLBACK SystemMonitor::PowerMessageWindow::WndProc(
+    HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam) {
+  switch (message) {
+    case WM_POWERBROADCAST: {
+      DWORD power_event = static_cast<DWORD>(message);
+      ProcessWmPowerBroadcastMessage(power_event);
+      return TRUE;
+    }
+    default:
+      break;
+  }
+  return ::DefWindowProc(hwnd, message, wparam, lparam);
+}
+
+// static
+LRESULT CALLBACK SystemMonitor::PowerMessageWindow::WndProcThunk(
+    HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam) {
+  PowerMessageWindow* message_hwnd =
+      reinterpret_cast<PowerMessageWindow*>(
+          GetWindowLongPtr(hwnd, GWLP_USERDATA));
+  if (message_hwnd)
+    return message_hwnd->WndProc(hwnd, message, wparam, lparam);
+  return ::DefWindowProc(hwnd, message, wparam, lparam);
+}
+#endif  // OS_WIN
+
+
 SystemMonitor::SystemMonitor()
     : power_observer_list_(new ObserverListThreadSafe<PowerObserver>()),
       devices_changed_observer_list_(
@@ -38,6 +152,9 @@ SystemMonitor::SystemMonitor()
 #if defined(OS_MACOSX)
   PlatformInit();
 #endif
+#if defined(OS_WIN)
+  power_message_window_.reset(new PowerMessageWindow);
+#endif
 }
 
 SystemMonitor::~SystemMonitor() {