Support plumbing LatencyInfo through the old software path.

content/browser/renderer_host/render_widget_host_view_aura.cc

Index: content/browser/renderer_host/render_widget_host_view_aura.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_aura.cc b/content/browser/renderer_host/render_widget_host_view_aura.cc
index 30d1fb79d8b6b9d09a9add8950f41a2189526e55..bccbfaf06870803ba19e9f02d5f2ed732d248827 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura.cc
+++ b/content/browser/renderer_host/render_widget_host_view_aura.cc
@@ -1028,10 +1028,13 @@ void RenderWidgetHostViewAura::ImeCompositionRangeChanged(
 void RenderWidgetHostViewAura::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) {
   if (accelerated_compositing_state_changed_)
     UpdateExternalTexture();
 
+  software_latency_info_.MergeWith(latency_info);

[piman, 2013/06/07 02:51:30]

Does this grow arbitrarily? If the tab is updating while offscreen, I'm afraid
we won't be calling OnPaint. Can this be a problem?

[jbauman, 2013/06/07 07:28:24]

No, this structure was designed not to grow, for this very reason.

+
   // Use the state of the RenderWidgetHost and not the window as the two may
   // differ. In particular if the window is hidden but the renderer isn't and we
   // ignore the update and the window is made visible again the layer isn't
@@ -2230,6 +2233,11 @@ void RenderWidgetHostViewAura::OnPaint(gfx::Canvas* canvas) {
 
     if (paint_observer_)
       paint_observer_->OnPaintComplete();
+    ui::Compositor* compositor = GetCompositor();
+    if (compositor) {
+      compositor->SetLatencyInfo(software_latency_info_);
+      software_latency_info_.Clear();
+    }
   } else if (aura::Env::GetInstance()->render_white_bg()) {
     canvas->DrawColor(SK_ColorWHITE);
   }