Bring skydebugger closer to clean-shutdown

mojo/services/view_manager/display_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 "mojo/services/view_manager/display_manager.h"
 
 #include "base/numerics/safe_conversions.h"
 #include "cc/surfaces/surface_id_allocator.h"
 #include "mojo/converters/geometry/geometry_type_converters.h"
 #include "mojo/converters/surfaces/surfaces_type_converters.h"
@@ skipping 138 matching lines @@
   frame->passes.push_back(pass.Pass());
   frame->resources.resize(0u);
   surface_->SubmitFrame(SurfaceId::From(surface_id_), frame.Pass());
 
   native_viewport_->SubmittedFrame(SurfaceId::From(surface_id_));
 
   dirty_rect_ = gfx::Rect();
 }
 
 void DisplayManager::OnDestroyed() {
+  // This is called when the native_viewport is torn down before
+  // ~DisplayManager may be called.
   native_viewport_closed_callback_.Run();
 }
 
 void DisplayManager::OnSizeChanged(SizePtr size) {
   size_ = size.To<gfx::Size>();
   connection_manager_->root()->SetBounds(gfx::Rect(size_));
   if (surface_id_.is_null())
     return;
   surface_->DestroySurface(SurfaceId::From(surface_id_));
   surface_id_ = cc::SurfaceId();
   SchedulePaint(connection_manager_->root(), gfx::Rect(size_));
 }
 
 void DisplayManager::ReturnResources(Array<ReturnedResourcePtr> resources) {
   DCHECK_EQ(0u, resources.size());
 }
 
 }  // namespace service
 }  // namespace mojo