cc: Plumbing for BeginFrameSource based on Surfaces

cc/surfaces/surface_aggregator.cc

Index: cc/surfaces/surface_aggregator.cc
diff --git a/cc/surfaces/surface_aggregator.cc b/cc/surfaces/surface_aggregator.cc
index 69618ba8b4ca4507f77705db7fa2834e2a07e452..a81f54791db9ffd4faa01ca437a00bb84c66b5ea 100644
--- a/cc/surfaces/surface_aggregator.cc
+++ b/cc/surfaces/surface_aggregator.cc
@@ -461,8 +461,20 @@ void SurfaceAggregator::RemoveUnreferencedChildren() {
       }
 
       Surface* surface_ptr = manager_->GetSurfaceForId(surface.first);
-      if (surface_ptr)
+      if (surface_ptr) {
         surface_ptr->RunDrawCallbacks(SurfaceDrawStatus::DRAW_SKIPPED);
+        // FIXME(brianderson): Make the aggregator take the display_ object.
+        surface_ptr->RemoveDisplay(display_);
+      }
+    }
+  }
+
+  for (const auto& surface : contained_surfaces_) {
+    if (!previous_contained_surfaces_.count(surface.first)) {
+      Surface* surface_ptr = manager_->GetSurfaceForId(surface.first);
+      if (surface_ptr) {
+        surface_ptr->AddDisplay(display_);
+      }
     }
   }
 }