Allow Windows to return a monitor out of the first quadrant

webrtc/modules/desktop_capture/win/dxgi_duplicator_controller.h

Index: webrtc/modules/desktop_capture/win/dxgi_duplicator_controller.h
diff --git a/webrtc/modules/desktop_capture/win/dxgi_duplicator_controller.h b/webrtc/modules/desktop_capture/win/dxgi_duplicator_controller.h
index 364690bcb933ed667038993210cb4943e6ad4cc7..c9838ad7a1e5d63c918da9b22fcde0c0276d0dac 100644
--- a/webrtc/modules/desktop_capture/win/dxgi_duplicator_controller.h
+++ b/webrtc/modules/desktop_capture/win/dxgi_duplicator_controller.h
@@ -158,9 +158,7 @@ class DxgiDuplicatorController {
   // The minimum GetNumFramesCaptured() returned by |duplicators_|.
   int64_t GetNumFramesCaptured() const;
 
-  // Returns a DesktopSize to cover entire desktop_rect. This may be different
-  // than desktop_rect().size(), since top-left of the screen does not need to
-  // be started from (0, 0).
+  // Returns a DesktopSize to cover entire |desktop_rect_|.
   DesktopSize desktop_size() const;
 
   // Returns the size of one screen. |id| should be >= 0. If system does not
@@ -181,6 +179,12 @@ class DxgiDuplicatorController {
   // during first several capture attempts.
   bool EnsureFrameCaptured(Context* context, SharedDesktopFrame* target);
 
+  // Moves |desktop_rect_| and all underlying |duplicators_|, putting top left
+  // corner of the desktop at (0, 0). This is necessary because DXGI_OUTPUT_DESC
+  // may return negative coordinates. Called from DoInitialize() after all
+  // DxgiAdapterDuplicator and DxgiOutputDuplicator instances are initialized.
+  void TranslateRect();
+
   // This lock must be locked whenever accessing any of the following objects.
   rtc::CriticalSection lock_;