SurfaceIds must be reusable as soon as their surfaces are marked destroyed

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 70 matching lines @@
 void SurfaceManager::SetDependencyTracker(
     std::unique_ptr<SurfaceDependencyTracker> dependency_tracker) {
   dependency_tracker_ = std::move(dependency_tracker);
 }
 
 void SurfaceManager::RequestSurfaceResolution(Surface* pending_surface) {
   if (dependency_tracker_)
     dependency_tracker_->RequestSurfaceResolution(pending_surface);
 }
 
-void SurfaceManager::RegisterSurface(Surface* surface) {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  DCHECK(surface);
-  DCHECK(!surface_map_.count(surface->surface_id()));
-  surface_map_[surface->surface_id()] = surface;
-}
-
 void SurfaceManager::DeregisterSurface(const SurfaceId& surface_id) {
   DCHECK(thread_checker_.CalledOnValidThread());
   SurfaceMap::iterator it = surface_map_.find(surface_id);
   DCHECK(it != surface_map_.end());
   surface_map_.erase(it);
   RemoveAllSurfaceReferences(surface_id);
 }
 
-void SurfaceManager::Destroy(std::unique_ptr<Surface> surface) {
+std::unique_ptr<Surface> SurfaceManager::CreateSurface(
+    base::WeakPtr<SurfaceFactory> surface_factory,
+    const LocalSurfaceId& local_surface_id) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(local_surface_id.is_valid() && surface_factory);
+
+  SurfaceId surface_id(surface_factory->frame_sink_id(), local_surface_id);
+
+  // If no surface with this SurfaceId exists, simply create the surface and
+  // return.
+  auto surface_iter = surface_map_.find(surface_id);
+  if (surface_iter == surface_map_.end()) {
+    auto surface = base::MakeUnique<Surface>(surface_id, surface_factory);
+    surface_map_[surface->surface_id()] = surface.get();
+    return surface;
+  }
+
+  // If a surface with this SurfaceId exists and it's not marked as destroyed,
+  // we should not receive a request to create a new surface with the same
+  // SurfaceId.
+  DCHECK(surface_iter->second->destroyed());
+
+  // If a surface with this SurfaceId exists and it's marked as destroyed,
+  // it means it's in the garbage collector's queue. We simply take it out of
+  // the queue and reuse it.
+  auto it =
+      std::find_if(surfaces_to_destroy_.begin(), surfaces_to_destroy_.end(),
+                   [&surface_id](const std::unique_ptr<Surface>& surface) {
+                     return surface->surface_id() == surface_id;
+                   });
+  DCHECK(it != surfaces_to_destroy_.end());
+  std::unique_ptr<Surface> surface = std::move(*it);
+  surfaces_to_destroy_.erase(it);
+  surface->set_destroyed(false);
+  DCHECK_EQ(surface_factory.get(), surface->factory().get());
+  return surface;
+}
+
+void SurfaceManager::DestroySurface(std::unique_ptr<Surface> surface) {
   DCHECK(thread_checker_.CalledOnValidThread());
   surface->set_destroyed(true);
   surfaces_to_destroy_.push_back(std::move(surface));
   GarbageCollectSurfaces();
 }
 
 void SurfaceManager::RequireSequence(const SurfaceId& surface_id,
                                      const SurfaceSequence& sequence) {
   auto* surface = GetSurfaceForId(surface_id);
   if (!surface) {
@@ skipping 540 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