Retain references to surfaces from both active AND pending CompositorFrames

cc/surfaces/surface_manager.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/surfaces/surface_manager.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <queue>
@@ skipping 309 matching lines @@
       live_surfaces.push_back(surface_id);
     }
   }
 
   // Mark all surfaces reachable from live surfaces by adding them to
   // live_surfaces and live_surfaces_set.
   for (size_t i = 0; i < live_surfaces.size(); i++) {
     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;
 
       Surface* surf2 = GetSurfaceForId(id);
       if (surf2) {
         live_surfaces.push_back(id);
         live_surfaces_set.insert(id);
       }
     }
   }
@@ skipping 292 matching lines @@
     std::vector<SurfaceId> children(iter->second.begin(), iter->second.end());
     std::sort(children.begin(), children.end());
 
     for (const SurfaceId& child_id : children)
       SurfaceReferencesToStringImpl(child_id, indent + "  ", str);
   }
 }
 #endif  // DCHECK_IS_ON()
 
 }  // namespace cc