[UI] - less impact to limiting frames

src/xenia/gpu/command_processor.cc

@@ -839,8 +839,6 @@ bool CommandProcessor::ExecutePacketType3_XE_SWAP(RingBuffer* reader,
       swap_update_time_ns_ = xe::Clock::QueryHostSystemTime();
     } else {
       xe::threading::MaybeYield();
-      xe::threading::Sleep(std::chrono::nanoseconds((swap_update_time_ns_ +
-		  16666) - xe::Clock::QueryHostSystemTime()));
     }
   }
   return true;

src/xenia/ui/window.cc

@@ -187,8 +187,7 @@ void Window::OnPaint(UIEvent* e) {
     if (now_ns > fps_update_time_ns_ + 16666) {
       // do nothing
     } else {
-      xe::threading::Sleep(std::chrono::nanoseconds((fps_update_time_ns_ +
-		  16666) - now_ns));
+      xe::threading::MaybeYield();
     }
   }