Change HostResolver::Resolve() to take an std::unique_ptr<Request>* rather than a RequestHandle*

net/dns/host_resolver_mojo.cc

Index: net/dns/host_resolver_mojo.cc
diff --git a/net/dns/host_resolver_mojo.cc b/net/dns/host_resolver_mojo.cc
index 42801461c0a6121a7cad04f7de50b36f6e80f1aa..d0ffedfd415662d0bdd0c1140c0ee896510068d1 100644
--- a/net/dns/host_resolver_mojo.cc
+++ b/net/dns/host_resolver_mojo.cc
@@ -36,6 +36,11 @@ class HostResolverMojo::Job : public interfaces::HostResolverRequestClient {
       mojo::InterfaceRequest<interfaces::HostResolverRequestClient> request,
       base::WeakPtr<HostCache> host_cache);
 
+  void SetRequest(RequestImpl* req) {
+    DCHECK(req);
+    request_ = req;
+  }
+
  private:
   // interfaces::HostResolverRequestClient override.
   void ReportResult(int32_t error,
@@ -49,6 +54,29 @@ class HostResolverMojo::Job : public interfaces::HostResolverRequestClient {
   CompletionCallback callback_;
   mojo::Binding<interfaces::HostResolverRequestClient> binding_;
   base::WeakPtr<HostCache> host_cache_;
+  RequestImpl* request_;
+};
+
+class HostResolverMojo::RequestImpl : public HostResolver::Request {
+ public:
+  explicit RequestImpl(std::unique_ptr<Job> job) : job_(std::move(job)) {
+    DCHECK(job_);
+    job_->SetRequest(this);
+  }
+
+  ~RequestImpl() override {}
+
+  void ChangeRequestPriority(RequestPriority priority) override {}
+
+  void RemoveJob() {
+    if (job_)
+      job_.reset();
+  }
+
+ private:
+  std::unique_ptr<Job> job_;
+
+  DISALLOW_COPY_AND_ASSIGN(RequestImpl);
 };
 
 HostResolverMojo::HostResolverMojo(Impl* impl)
@@ -63,7 +91,7 @@ int HostResolverMojo::Resolve(const RequestInfo& info,
                               RequestPriority priority,
                               AddressList* addresses,
                               const CompletionCallback& callback,
-                              RequestHandle* request_handle,
+                              std::unique_ptr<Request>* request_handle,
                               const BoundNetLog& source_net_log) {
   DCHECK(thread_checker_.CalledOnValidThread());
   DVLOG(1) << "Resolve " << info.host_port_pair().ToString();
@@ -77,8 +105,11 @@ int HostResolverMojo::Resolve(const RequestInfo& info,
   }
 
   interfaces::HostResolverRequestClientPtr handle;
-  *request_handle = new Job(key, addresses, callback, mojo::GetProxy(&handle),
-                            host_cache_weak_factory_.GetWeakPtr());
+  std::unique_ptr<Job> job(new Job(key, addresses, callback,
+                                   mojo::GetProxy(&handle),
+                                   host_cache_weak_factory_.GetWeakPtr()));
+  (*request_handle).reset(new RequestImpl(std::move(job)));
+
   impl_->ResolveDns(interfaces::HostResolverRequestInfo::From(info),
                     std::move(handle));
   return ERR_IO_PENDING;
@@ -92,18 +123,6 @@ int HostResolverMojo::ResolveFromCache(const RequestInfo& info,
   return ResolveFromCacheInternal(info, CacheKeyForRequest(info), addresses);
 }
 
-void HostResolverMojo::ChangeRequestPriority(RequestHandle req,
-                                             RequestPriority priority) {
-  // Do nothing, since Resolve() discarded the priority anyway.
-}
-
-void HostResolverMojo::CancelRequest(RequestHandle req) {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  // Deleting the Job closes the HostResolverRequestClient connection,
-  // signalling cancellation of the request.
-  delete static_cast<Job*>(req);
-}
-
 HostCache* HostResolverMojo::GetHostCache() {
   return host_cache_.get();
 }
@@ -149,8 +168,15 @@ void HostResolverMojo::Job::ReportResult(
     HostCache::Entry entry(error, *addresses_, ttl);
     host_cache_->Set(key_, entry, base::TimeTicks::Now(), ttl);
   }
-  callback_.Run(error);
-  delete this;
+
+  CompletionCallback cb = callback_;
+  callback_.Reset();
+
+  DCHECK(request_);
+  request_->RemoveJob();
+
+  if (!cb.is_null())
+    cb.Run(error);
 }
 
 void HostResolverMojo::Job::OnConnectionError() {