Repaint windows on screen unlock.

ui/views/win/hwnd_message_handler.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 "ui/views/win/hwnd_message_handler.h"
 
 #include <dwmapi.h>
 #include <shellapi.h>
+#include <wtsapi32.h>
+#pragma comment(lib, "wtsapi32.lib")
 
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
 #include "base/win/win_util.h"
 #include "base/win/windows_version.h"
 #include "ui/base/touch/touch_enabled.h"
 #include "ui/base/win/mouse_wheel_util.h"
 #include "ui/base/win/shell.h"
 #include "ui/base/win/touch_input.h"
 #include "ui/events/event.h"
@@ skipping 1359 matching lines @@
   // Look into moving the WS_VSCROLL and WS_HSCROLL style setting logic to the
   // CalculateWindowStylesFromInitParams function. Doing it there seems to
   // cause some interactive tests to fail. Investigation needed.
   if (IsTopLevelWindow(hwnd())) {
     long current_style = ::GetWindowLong(hwnd(), GWL_STYLE);
     ::SetWindowLong(hwnd(), GWL_STYLE,
                     current_style | WS_VSCROLL | WS_HSCROLL);
     scroll_styles_set_ = true;
   }
 #endif
+  WTSRegisterSessionNotification(hwnd(), NOTIFY_FOR_THIS_SESSION);

[sky, 2014/01/16 16:36:37]

Docs indicate you need to unregister.

+
   // TODO(beng): move more of NWW::OnCreate here.
   return 0;
 }
 
 void HWNDMessageHandler::OnDestroy() {
   delegate_->HandleDestroying();
 }
 
 void HWNDMessageHandler::OnDisplayChange(UINT bits_per_pixel,
                                          const CSize& screen_size) {
@@ skipping 916 matching lines @@
     MARGINS m = {10, 10, 10, 10};
     DwmExtendFrameIntoClientArea(hwnd(), &m);
   }
   if (window_pos->flags & SWP_SHOWWINDOW)
     delegate_->HandleVisibilityChanged(true);
   else if (window_pos->flags & SWP_HIDEWINDOW)
     delegate_->HandleVisibilityChanged(false);
   SetMsgHandled(FALSE);
 }
 
+void HWNDMessageHandler::ForceRedrawWindow(int attempts) {
+  HDESK input_desktop = ::OpenInputDesktop(0, 0, GENERIC_READ);
+  if (!input_desktop) {

[cpu_(ooo_6.6-7.5), 2014/01/16 18:35:08]

son, I am not sure what you are trying to do here but I think you meant to
detect the interactive desktop

Use GetThreadDesktop and GetUserObjectInformation(UOI_IO).

Also this function as is is more expensive than its name implies, how about

bool IsInteactiveDesktop();

void HWNDMessageHandler::OnSessionChange(WPARAM status_code, ..) {
  static int count = 0;
  if (status_code == WTS_SESSION_UNLOCK)
    if (!IsInteractiveDesktop())
       PostTask(... OnSessionChange)


}

+    // Presents will continue to fail as long as the input desktop is
+    // unavailable.
+    if (--attempts <= 0)
+      return;
+    base::MessageLoop::current()->PostDelayedTask(
+        FROM_HERE,
+        base::Bind(&HWNDMessageHandler::ForceRedrawWindow,
+                   weak_factory_.GetWeakPtr(),
+                   attempts),
+        base::TimeDelta::FromMilliseconds(500));
+    return;
+  }
+  ::CloseDesktop(input_desktop);
+  InvalidateRect(hwnd(), NULL, FALSE);
+}
+
+void HWNDMessageHandler::OnSessionChange(WPARAM status_code,
+                                         PWTSSESSION_NOTIFICATION session_id) {
+  // Direct3D presents are ignored while the screen is locked, so force the
+  // window to be redrawn on unlock.
+  if (status_code == WTS_SESSION_UNLOCK)
+    ForceRedrawWindow(10);
+
+  SetMsgHandled(FALSE);
+}
+
 void HWNDMessageHandler::HandleTouchEvents(const TouchEvents& touch_events) {
   base::WeakPtr<HWNDMessageHandler> ref(weak_factory_.GetWeakPtr());
   for (size_t i = 0; i < touch_events.size() && ref; ++i)
     delegate_->HandleTouchEvent(touch_events[i]);
 }
 
 }  // namespace views