Aura-Mus: Allocate a LocalSurfaceId on size change

ui/aura/mus/window_tree_client.cc

Index: ui/aura/mus/window_tree_client.cc
diff --git a/ui/aura/mus/window_tree_client.cc b/ui/aura/mus/window_tree_client.cc
index 233da4df7e06e9473645b9a46992700723fd34e0..4efa8dced76863b273a6f1d85a29eeb284df866b 100644
--- a/ui/aura/mus/window_tree_client.cc
+++ b/ui/aura/mus/window_tree_client.cc
@@ -614,12 +614,16 @@ void WindowTreeClient::ScheduleInFlightBoundsChange(
     WindowMus* window,
     const gfx::Rect& old_bounds,
     const gfx::Rect& new_bounds) {
-  // TODO(fsamuel): Allocate a new LocalSurfaceId on size change.
   const uint32_t change_id =
       ScheduleInFlightChange(base::MakeUnique<InFlightBoundsChange>(
-          this, window, old_bounds, base::nullopt));
+          this, window, old_bounds, window->GetLocalSurfaceId()));
+  base::Optional<cc::LocalSurfaceId> local_surface_id;
+  if ((window->window_mus_type() == WindowMusType::TOP_LEVEL_IN_WM ||
+       window->window_mus_type() == WindowMusType::EMBED_IN_OWNER)) {
+    local_surface_id = window->GetOrAllocateLocalSurfaceId(new_bounds.size());
+  }
   tree_->SetWindowBounds(change_id, window->server_id(), new_bounds,
-                         base::nullopt);
+                         local_surface_id);

[sky, 2017/03/29 00:07:35]

Please add test coverage that the id sent to the server changes when the bounds
change. It would also be good to verify the revert logic works correctly for
local_surface_ids.

[Fady Samuel, 2017/03/29 22:10:14]

Done! Found a bug a fixed it. I've added two tests and modified an existing test
to verify changes to LocalSurfaceId.

This could stand to use more test coverage. I will add more in my subsequent CL.

 }
 
 void WindowTreeClient::OnWindowMusCreated(WindowMus* window) {