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

net/proxy/proxy_resolver_v8_tracing.cc

Index: net/proxy/proxy_resolver_v8_tracing.cc
diff --git a/net/proxy/proxy_resolver_v8_tracing.cc b/net/proxy/proxy_resolver_v8_tracing.cc
index ef25fc80ece4bdbfa1fff4cf64a88c313bc5bb75..9eb21b3e19ffb99ef14c2790e0adab0b3b5b5e44 100644
--- a/net/proxy/proxy_resolver_v8_tracing.cc
+++ b/net/proxy/proxy_resolver_v8_tracing.cc
@@ -284,7 +284,7 @@ class Job : public base::RefCountedThreadSafe<Job>,
   // Handle to the outstanding request in the HostResolver, or NULL.
   // This is mutated and used on the origin thread, however it may be read by
   // the worker thread for some DCHECKS().
-  HostResolver::RequestHandle pending_dns_;
+  std::unique_ptr<HostResolver::Request> pending_dns_;
 
   // Indicates if the outstanding DNS request completed synchronously. Written
   // on the origin thread, and read by the worker thread.
@@ -339,7 +339,7 @@ Job::Job(const Job::Params* params,
       event_(base::WaitableEvent::ResetPolicy::MANUAL,
              base::WaitableEvent::InitialState::NOT_SIGNALED),
       last_num_dns_(0),
-      pending_dns_(NULL) {
+      pending_dns_(nullptr) {
   CheckIsOnOriginThread();
 }
 
@@ -395,8 +395,7 @@ void Job::Cancel() {
   ReleaseCallback();
 
   if (pending_dns_) {
-    host_resolver()->CancelRequest(pending_dns_);
-    pending_dns_ = NULL;
+    pending_dns_.reset();
   }
 
   // The worker thread might be blocked waiting for DNS.
@@ -710,7 +709,7 @@ void Job::DoDnsOperation() {
   if (cancelled_.IsSet())
     return;
 
-  HostResolver::RequestHandle dns_request = NULL;
+  std::unique_ptr<HostResolver::Request> dns_request;
   int result = host_resolver()->Resolve(
       MakeDnsRequestInfo(pending_dns_host_, pending_dns_op_), DEFAULT_PRIORITY,
       &pending_dns_addresses_, base::Bind(&Job::OnDnsOperationComplete, this),
@@ -728,7 +727,7 @@ void Job::DoDnsOperation() {
     OnDnsOperationComplete(result);
   } else {
     DCHECK(dns_request);
-    pending_dns_ = dns_request;
+    pending_dns_ = std::move(dns_request);
     // OnDnsOperationComplete() will be called by host resolver on completion.
   }