[Chromoting] Improve DirectX capturer to support multiple outputs

webrtc/modules/desktop_capture/desktop_geometry.cc

Index: webrtc/modules/desktop_capture/desktop_geometry.cc
diff --git a/webrtc/modules/desktop_capture/desktop_geometry.cc b/webrtc/modules/desktop_capture/desktop_geometry.cc
index 1ff7c683c79828a0d8c4e5f9c4c4cb23fd365243..4c79688d35775160ba35dea9fdfb01743d95809b 100644
--- a/webrtc/modules/desktop_capture/desktop_geometry.cc
+++ b/webrtc/modules/desktop_capture/desktop_geometry.cc
@@ -37,6 +37,13 @@ void DesktopRect::IntersectWith(const DesktopRect& rect) {
   }
 }
 
+void DesktopRect::JoinWith(const DesktopRect& rect) {
+  left_ = std::min(left(), rect.left());
+  top_ = std::min(top(), rect.top());
+  right_ = std::max(right(), rect.right());
+  bottom_ = std::max(bottom(), rect.bottom());
+}
+
 void DesktopRect::Translate(int32_t dx, int32_t dy) {
   left_ += dx;
   top_ += dy;