ui::ContextFactory should not create SurfaceIdAllocators

content/browser/compositor/gpu_process_transport_factory.cc

Index: content/browser/compositor/gpu_process_transport_factory.cc
diff --git a/content/browser/compositor/gpu_process_transport_factory.cc b/content/browser/compositor/gpu_process_transport_factory.cc
index 821f642ac2a9ee5cfa4d12fa336c1345a82859fe..79b14c1a515177b070f1167199d058b1eadc5c0c 100644
--- a/content/browser/compositor/gpu_process_transport_factory.cc
+++ b/content/browser/compositor/gpu_process_transport_factory.cc
@@ -687,13 +687,11 @@ ui::ContextFactory* GpuProcessTransportFactory::GetContextFactory() {
   return this;
 }
 
-std::unique_ptr<cc::SurfaceIdAllocator>
-GpuProcessTransportFactory::CreateSurfaceIdAllocator() {
-  std::unique_ptr<cc::SurfaceIdAllocator> allocator =
-      base::WrapUnique(new cc::SurfaceIdAllocator(next_surface_client_id_++));
+uint32_t GpuProcessTransportFactory::AllocateSurfaceClientId() {
+  uint32_t client_id = next_surface_client_id_++;
   if (GetSurfaceManager())
-    allocator->RegisterSurfaceClientId(GetSurfaceManager());
-  return allocator;
+    GetSurfaceManager()->RegisterSurfaceClientId(client_id);

[piman, 2016/07/21 17:19:47]

So, the previous code also relied on SurfaceIdAllocator::RegisterSurfaceClientId
setting up the manager_ field on the the SurfaceIdAllocator, so that in
~SurfaceIdAllocator, SurfaceManager::InvalidateSurfaceClientId is called.

The latter doesn't happen any more. Is it not needed?

[Fady Samuel, 2016/07/21 17:22:23]

Well, it is still needed, but SurfaceIdAllocator will take care of that on
destruction so the code shouldn't be any different here. In the end state, this
won't be needed though because SurfaceFactory will take in a client ID and do
all the necessary set up and tear down work.

[piman, 2016/07/21 17:28:40]

With this patch, the SurfaceIdAllocator doesn't know about the SurfaceManager
any more, so skips InvalidateSurfaceClientId in the destructor (manager_ would
be null - unless I missed something?)
Got it.

[Fady Samuel, 2016/07/21 20:43:33]

I've made all the clients that create SurfaceIdAllocators Register and
invalidate the client IDs themselves. This takes us in the right direction for
bundling this into SurfaceFactory in a subsequent CL.

+  return client_id;
 }
 
 void GpuProcessTransportFactory::ResizeDisplay(ui::Compositor* compositor,