Support plumbing LatencyInfo through the old software path.

content/browser/renderer_host/render_widget_host_view_win.cc

Index: content/browser/renderer_host/render_widget_host_view_win.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_win.cc b/content/browser/renderer_host/render_widget_host_view_win.cc
index 4d8c33415069afc338cbc82e63e067df1491b1dc..b151d47f7bc688e1abfcb8519505d723854ddc35 100644
--- a/content/browser/renderer_host/render_widget_host_view_win.cc
+++ b/content/browser/renderer_host/render_widget_host_view_win.cc
@@ -749,7 +749,9 @@ void RenderWidgetHostViewWin::Redraw() {
 void RenderWidgetHostViewWin::DidUpdateBackingStore(
     const gfx::Rect& scroll_rect,
     const gfx::Vector2d& scroll_delta,
-    const std::vector<gfx::Rect>& copy_rects) {
+    const std::vector<gfx::Rect>& copy_rects,
+    const ui::LatencyInfo& latency_info) {
+  software_latency_info_.MergeWith(latency_info);
   if (is_hidden_)
     return;
 
@@ -1394,6 +1396,10 @@ void RenderWidgetHostViewWin::OnPaint(HDC unused_dc) {
       // recorded.
       web_contents_switch_paint_time_ = TimeTicks();
     }
+
+    software_latency_info_.swap_timestamp = TimeTicks::HighResNow();
+    render_widget_host_->FrameSwapped(software_latency_info_);
+    software_latency_info_.Clear();
   } else {
     DrawBackground(paint_dc.m_ps.rcPaint, &paint_dc);
     if (whiteout_start_time_.is_null())