desktop_capture: crop border in window_capture on Win8/10

webrtc/modules/desktop_capture/win/window_capture_utils.cc

 /*
  *  Copyright (c) 2014 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/win/window_capture_utils.h"
 
+#include "webrtc/rtc_base/win32.h"
+
 namespace webrtc {
 
 bool
 GetCroppedWindowRect(HWND window,
                      DesktopRect* cropped_rect,
                      DesktopRect* original_rect) {
   RECT rect;
   if (!GetWindowRect(window, &rect)) {
     return false;
   }
   WINDOWPLACEMENT window_placement;
   window_placement.length = sizeof(window_placement);
   if (!GetWindowPlacement(window, &window_placement)) {
     return false;
   }
 
   *original_rect = DesktopRect::MakeLTRB(
       rect.left, rect.top, rect.right, rect.bottom);
 
-  if (window_placement.showCmd == SW_SHOWMAXIMIZED) {
+  // After Windows8, transparent borders will be added by OS at
+  // left/bottom/right sides of a window. If the cropped window
+  // doesn't remove these borders, the background will be exposed a bit.
+  if (rtc::IsWindows8OrLater() ||
+      window_placement.showCmd == SW_SHOWMAXIMIZED) {
     DesktopSize border = DesktopSize(GetSystemMetrics(SM_CXSIZEFRAME),
                                      GetSystemMetrics(SM_CYSIZEFRAME));
     *cropped_rect = DesktopRect::MakeLTRB(
         rect.left + border.width(),
         rect.top,
         rect.right - border.width(),
         rect.bottom - border.height());
   } else {
     *cropped_rect = *original_rect;
   }
@@ skipping 17 matching lines @@
 
 bool AeroChecker::IsAeroEnabled() {
   BOOL result = FALSE;
   if (func_) {
     func_(&result);
   }
   return result != FALSE;
 }
 
 }  // namespace webrtc