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

webrtc/modules/desktop_capture/window_capturer_win.cc

Index: webrtc/modules/desktop_capture/window_capturer_win.cc
diff --git a/webrtc/modules/desktop_capture/window_capturer_win.cc b/webrtc/modules/desktop_capture/window_capturer_win.cc
index ba45eaa9d18a78d15ee3ed0c6c285e76bf089eb1..322a5340c9e48c500de94a758c2790723a304a2d 100644
--- a/webrtc/modules/desktop_capture/window_capturer_win.cc
+++ b/webrtc/modules/desktop_capture/window_capturer_win.cc
@@ -13,6 +13,7 @@
 #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"
@@ -39,13 +40,26 @@ BOOL CALLBACK WindowsEnumerationHandler(HWND hwnd, LPARAM param) {
   // 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);