Handful of changes to get mus to shutdown correctly

components/mus/ws/platform_display.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 "components/mus/ws/platform_display.h"
 
 #include "base/numerics/safe_conversions.h"
 #include "build/build_config.h"
 #include "cc/output/compositor_frame.h"
 #include "cc/output/copy_output_request.h"
@@ skipping 182 matching lines @@
   platform_window_ =
       ui::OzonePlatform::GetInstance()->CreatePlatformWindow(this, bounds);
 #else
   NOTREACHED() << "Unsupported platform";
 #endif
   platform_window_->SetBounds(bounds);
   platform_window_->Show();
 }
 
 DefaultPlatformDisplay::~DefaultPlatformDisplay() {
-  delegate_->OnTopLevelSurfaceChanged(cc::SurfaceId());
+  // Don't notify the delegate from the destructor.
+  delegate_ = nullptr;
+
   // Invalidate WeakPtrs now to avoid callbacks back into the
   // DefaultPlatformDisplay during destruction of |top_level_display_client_|.
   weak_factory_.InvalidateWeakPtrs();
   top_level_display_client_.reset();
   // Destroy the PlatformWindow early on as it may call us back during
   // destruction and we want to be in a known state. But destroy the surface
   // first because it can still be using the platform window.
   platform_window_.reset();
 }
 
@@ skipping 178 matching lines @@
     delegate_->OnEvent(char_event);
   }
 #endif
 }
 
 void DefaultPlatformDisplay::OnCloseRequest() {
   platform_window_->Close();
 }
 
 void DefaultPlatformDisplay::OnClosed() {
-  delegate_->OnDisplayClosed();
+  if (delegate_)
+    delegate_->OnDisplayClosed();
 }
 
 void DefaultPlatformDisplay::OnWindowStateChanged(
     ui::PlatformWindowState new_state) {}
 
 void DefaultPlatformDisplay::OnLostCapture() {
   delegate_->OnNativeCaptureLost();
 }
 
 void DefaultPlatformDisplay::OnAcceleratedWidgetAvailable(
@@ skipping 16 matching lines @@
 
 void DefaultPlatformDisplay::RequestCopyOfOutput(
     scoped_ptr<cc::CopyOutputRequest> output_request) {
   if (top_level_display_client_)
     top_level_display_client_->RequestCopyOfOutput(std::move(output_request));
 }
 
 }  // namespace ws
 
 }  // namespace mus