Shut down Profile's URLRequestContextGetters safely.

chrome/browser/net/chrome_url_request_context_getter.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 "chrome/browser/net/chrome_url_request_context_getter.h"
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
 #include "base/message_loop/message_loop.h"
 #include "base/message_loop/message_loop_proxy.h"
@@ skipping 152 matching lines @@
 
 }  // namespace
 
 // ----------------------------------------------------------------------------
 // ChromeURLRequestContextGetter
 // ----------------------------------------------------------------------------
 
 ChromeURLRequestContextGetter::ChromeURLRequestContextGetter(
     ChromeURLRequestContextFactory* factory)
     : factory_(factory),
-      url_request_context_(NULL) {
+      url_request_context_(nullptr) {
   DCHECK(factory);
 }
 
-ChromeURLRequestContextGetter::~ChromeURLRequestContextGetter() {}
+ChromeURLRequestContextGetter::~ChromeURLRequestContextGetter() {
+  // NotifyContextShuttingDown() must have been called.
+  DCHECK(!factory_.get());
+  DCHECK(!url_request_context_);
+}
 
 // Lazily create a URLRequestContext using our factory.
 net::URLRequestContext*
 ChromeURLRequestContextGetter::GetURLRequestContext() {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
   if (factory_.get()) {
     DCHECK(!url_request_context_);
     url_request_context_ = factory_->Create();
     factory_.reset();
   }
 
-  // Context reference is valid, unless we're trying to use the
-  // URLRequestContextGetter after the Profile has already been deleted.
-  CHECK(url_request_context_);
-
   return url_request_context_;
 }
 
-void ChromeURLRequestContextGetter::Invalidate() {
+void ChromeURLRequestContextGetter::NotifyContextShuttingDown() {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
+
   factory_.reset();
-  url_request_context_ = NULL;
+  url_request_context_ = nullptr;
+  URLRequestContextGetter::NotifyContextShuttingDown();
 }
 
 scoped_refptr<base::SingleThreadTaskRunner>
 ChromeURLRequestContextGetter::GetNetworkTaskRunner() const {
   return BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO);
 }
 
 // static
 ChromeURLRequestContextGetter* ChromeURLRequestContextGetter::Create(
     Profile* profile,
@@ skipping 45 matching lines @@
 ChromeURLRequestContextGetter*
 ChromeURLRequestContextGetter::CreateForIsolatedMedia(
     Profile* profile,
     ChromeURLRequestContextGetter* app_context,
     const ProfileIOData* profile_io_data,
     const StoragePartitionDescriptor& partition_descriptor) {
   return new ChromeURLRequestContextGetter(
       new FactoryForIsolatedMedia(
           profile_io_data, partition_descriptor, app_context));
 }