Wrap ScreenCapturer with ScreenCapturerDifferWrapper

webrtc/modules/desktop_capture/screen_capturer_unittest.cc

Index: webrtc/modules/desktop_capture/screen_capturer_unittest.cc
diff --git a/webrtc/modules/desktop_capture/screen_capturer_unittest.cc b/webrtc/modules/desktop_capture/screen_capturer_unittest.cc
index cb639b9e91e5c987190c58a2404fd1b8f5c6893a..39d9ee15be2c28790485081bb743d4ca0bfcdc0d 100644
--- a/webrtc/modules/desktop_capture/screen_capturer_unittest.cc
+++ b/webrtc/modules/desktop_capture/screen_capturer_unittest.cc
@@ -129,15 +129,21 @@ class ScreenCapturerTest : public testing::Test {
   }
 
 #if defined(WEBRTC_WIN)
+  // Enable allow_directx_capturer in DesktopCaptureOptions, but let
+  // ScreenCapturer::Create to decide whether a DirectX capturer should be used.
+  void MaybeCreateDirectxCapturer() {
+    DesktopCaptureOptions options(DesktopCaptureOptions::CreateDefault());
+    options.set_allow_directx_capturer(true);
+    capturer_.reset(ScreenCapturer::Create(options));
+  }
+
   bool CreateDirectxCapturer() {
     if (!ScreenCapturerWinDirectx::IsSupported()) {
       LOG(LS_WARNING) << "Directx capturer is not supported";
       return false;
     }
 
-    DesktopCaptureOptions options(DesktopCaptureOptions::CreateDefault());
-    options.set_allow_directx_capturer(true);
-    capturer_.reset(ScreenCapturer::Create(options));
+    MaybeCreateDirectxCapturer();
     return true;
   }
 
@@ -372,6 +378,13 @@ TEST_F(ScreenCapturerTest, TwoMagnifierCapturers) {
   TestCaptureUpdatedRegion({capturer_.get(), capturer2.get()});
 }
 
+TEST_F(ScreenCapturerTest, MaybeCaptureUpdatedRegionWithDirectxCapturer) {
+  // Even DirectX capturer is not supported in current system, we should be able
+  // to select a usable capturer.
+  MaybeCreateDirectxCapturer();
+  TestCaptureUpdatedRegion();
+}
+
 #endif  // defined(WEBRTC_WIN)
 
 }  // namespace webrtc