Make Mandoline shut down cleanly.

mandoline/ui/browser/browser.cc

 // Copyright 2015 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 "mandoline/ui/browser/browser.h"
 
 #include "base/command_line.h"
 #include "base/strings/utf_string_conversions.h"
 #include "components/view_manager/public/cpp/view.h"
 #include "components/view_manager/public/cpp/view_manager_init.h"
@@ skipping 22 matching lines @@
 Browser::Browser()
     : root_(nullptr),
       content_(nullptr),
       omnibox_(nullptr),
       navigator_host_(this),
       ui_(nullptr) {
   exposed_services_impl_.AddService(this);
 }
 
 Browser::~Browser() {
+  // Destruct ui_ manually while |this| is alive and reset the pointer first.
+  // This is to avoid a double delete when OnViewManagerDisconnected gets
+  // called.
+  delete ui_.release();
 }
 
 void Browser::ReplaceContentWithURL(const mojo::String& url) {
   Embed(url, nullptr, nullptr);
 }
 
 void Browser::Initialize(mojo::ApplicationImpl* app) {
   view_manager_init_.reset(new mojo::ViewManagerInit(app, this, this));
 
   ui_.reset(BrowserUI::Create(this, app));
@@ skipping 111 matching lines @@
 
   merged_service_provider_.reset(
       new MergedServiceProvider(exposed_services.Pass(), this));
   content_->Embed(url, services.Pass(),
                   merged_service_provider_->GetServiceProviderPtr().Pass());
 
   navigator_host_.RecordNavigation(url);
 }
 
 }  // namespace mandoline