Retain references to surfaces from both active AND pending CompositorFrames

cc/surfaces/surface_manager.cc

Index: cc/surfaces/surface_manager.cc
diff --git a/cc/surfaces/surface_manager.cc b/cc/surfaces/surface_manager.cc
index c91bf2cb617bef011f317c6cd7e1ed683402c6d1..f7e3119eb375b978ff7be255e5a77231f57dc509 100644
--- a/cc/surfaces/surface_manager.cc
+++ b/cc/surfaces/surface_manager.cc
@@ -327,7 +327,9 @@ SurfaceManager::SurfaceIdSet SurfaceManager::GetLiveSurfacesForSequences() {
     Surface* surf = surface_map_[live_surfaces[i]];
     DCHECK(surf);
 
-    for (const SurfaceId& id : surf->referenced_surfaces()) {
+    // TODO(fsamuel): We should probably keep alive pending referenced surfaces
+    // too.
+    for (const SurfaceId& id : surf->active_referenced_surfaces()) {
       if (live_surfaces_set.count(id))
         continue;