WebRtc Win Desktop capture: ignore Win8+ Modern Apps' windows.

webrtc/modules/desktop_capture/window_capturer_win.cc

 /*
  *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #include "webrtc/modules/desktop_capture/window_capturer.h"
 
 #include <assert.h>
 
 #include "webrtc/base/scoped_ptr.h"
+#include "webrtc/base/checks.h"
 #include "webrtc/base/win32.h"
 #include "webrtc/modules/desktop_capture/desktop_frame_win.h"
 #include "webrtc/modules/desktop_capture/win/window_capture_utils.h"
 #include "webrtc/system_wrappers/interface/logging.h"
 
 namespace webrtc {
 
 namespace {
 
 BOOL CALLBACK WindowsEnumerationHandler(HWND hwnd, LPARAM param) {
   WindowCapturer::WindowList* list =
       reinterpret_cast<WindowCapturer::WindowList*>(param);
 
   // Skip windows that are invisible, minimized, have no title, or are owned,
   // unless they have the app window style set.
   int len = GetWindowTextLength(hwnd);
   HWND owner = GetWindow(hwnd, GW_OWNER);
   LONG exstyle = GetWindowLong(hwnd, GWL_EXSTYLE);
   if (len == 0 || IsIconic(hwnd) || !IsWindowVisible(hwnd) ||
       (owner && !(exstyle & WS_EX_APPWINDOW))) {
     return TRUE;
   }
 
   // Skip the Program Manager window and the Start button.
   const size_t kClassLength = 256;
   WCHAR class_name[kClassLength];
-  GetClassName(hwnd, class_name, kClassLength);
+  const int class_name_length = GetClassName(hwnd, class_name, kClassLength);
+  RTC_DCHECK(class_name_length)
+      << "Error retrieving the application's class name";
+
   // Skip Program Manager window and the Start button. This is the same logic
   // that's used in Win32WindowPicker in libjingle. Consider filtering other
   // windows as well (e.g. toolbars).
   if (wcscmp(class_name, L"Progman") == 0 || wcscmp(class_name, L"Button") == 0)
     return TRUE;
 
+  // Windows 8 introduced a "Modern App" identified by their class name being
+  // either ApplicationFrameWindow or windows.UI.Core.coreWindow. The
+  // associated windows cannot be captured, so we skip them.
+  // http://crbug.com/526883.
+  if (rtc::IsWindows8OrLater() &&
+      (wcscmp(class_name, L"ApplicationFrameWindow") == 0 ||
+       wcscmp(class_name, L"Windows.UI.Core.CoreWindow") == 0)) {
+    return TRUE;
+  }
+
   WindowCapturer::Window window;
   window.id = reinterpret_cast<WindowCapturer::WindowId>(hwnd);
 
   const size_t kTitleLength = 500;
   WCHAR window_title[kTitleLength];
   // Truncate the title if it's longer than kTitleLength.
   GetWindowText(hwnd, window_title, kTitleLength);
   window.title = rtc::ToUtf8(window_title);
 
   // Skip windows when we failed to convert the title or it is empty.
@@ skipping 175 matching lines @@
 }
 
 }  // namespace
 
 // static
 WindowCapturer* WindowCapturer::Create(const DesktopCaptureOptions& options) {
   return new WindowCapturerWin();
 }
 
 }  // namespace webrtc