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..8abaaa6e956835c837000e2f95b823842be66566 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"
@@ -22,6 +23,8 @@ namespace webrtc {
 
 namespace {
 
+const int kMaxNameLength = 1024;
+
 BOOL CALLBACK WindowsEnumerationHandler(HWND hwnd, LPARAM param) {
   WindowCapturer::WindowList* list =
       reinterpret_cast<WindowCapturer::WindowList*>(param);
@@ -59,6 +62,23 @@ BOOL CALLBACK WindowsEnumerationHandler(HWND hwnd, LPARAM param) {
   if (window.title.empty())
     return TRUE;
 
+  // Filter out windows modern apps' windows that cannot be captured.
+  // Issue 526883
+  // Microsoft introduced modern app which can be used cross the Microsoft's
+  // platforms (Desktop, mobile phone and etc.) from Win8.
+  // Microsoft confirmed that those windows cannot be captured.
+  // Modern app's window class name will be ApplicationFrameWindow
+  // and/or windows.UI.Core.coreWindow.

[mcasas, 2015/10/01 21:59:17]

Suggestion of rephrase:
  // 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.

[gyzhou, 2015/10/02 18:30:34]

Done.

+  if (rtc::IsWindows8OrLater()) {
+    char class_name[kMaxNameLength];

[mcasas, 2015/10/01 21:59:17]

Why not reuse |kClassLength|? (l.43)

[gyzhou, 2015/10/02 18:30:34]

Done.

Since GetClassName() called in lin45. It makes sensor to move this part of code
up to remove some redundancy.

+    int class_name_length = GetClassNameA(hwnd, class_name, kMaxNameLength);

[mcasas, 2015/10/01 21:59:17]

const

[mcasas, 2015/10/01 21:59:17]

|class_name_length| or |classNameLength| ?

[gyzhou, 2015/10/02 18:30:35]

Done.

[gyzhou, 2015/10/02 18:30:35]

Done.

[gyzhou, 2015/10/02 18:30:35]

class_name_length is consistent with other part of the code.

+    RTC_DCHECK(class_name_length) <<
+        "Error retrieving the application's class name";
+    if (strcmp(class_name, "ApplicationFrameWindow") == 0 ||
+        strcmp(class_name, "Windows.UI.Core.CoreWindow") == 0)
+      return TRUE;
+  }
+
   list->push_back(window);
 
   return TRUE;