cc::SurfaceDependencyTracker should not crash when a Display goes away

cc/surfaces/surface_dependency_tracker.cc

Index: cc/surfaces/surface_dependency_tracker.cc
diff --git a/cc/surfaces/surface_dependency_tracker.cc b/cc/surfaces/surface_dependency_tracker.cc
index 652ecfe731b3d97edb77d43b00664451f00da6bf..3b37d6ca2470f0e783af162c750e159cf6783c4d 100644
--- a/cc/surfaces/surface_dependency_tracker.cc
+++ b/cc/surfaces/surface_dependency_tracker.cc
@@ -49,8 +49,7 @@ void SurfaceDependencyTracker::RequestSurfaceResolution(Surface* surface) {
           surface->surface_id());
   }
 
-  if (!blocked_surfaces_by_id_.count(surface->surface_id()))
-    blocked_surfaces_by_id_.insert(surface->surface_id());
+  blocked_surfaces_by_id_.insert(surface->surface_id());
 
   if (needs_deadline && !frames_since_deadline_set_)
     frames_since_deadline_set_ = 0;