SpdySessionPool: Invoke request deleted callbacks more discriminately.

Previously, we'd invoke them whenever any request was deleted or when a
SpdySession is created. With this CL, we invoke them only when the
first request is deleted or a SpdySession is created. This reduces the
number of PostTasks and searches through std::maps when we have a bunch
of requests all waiting on the creation of the same SpdySession.

Bug: 912727
Change-Id: I5083137cf0726e3b1ddb3ac4608b706121964cbf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1570914
Commit-Queue: Matt Menke <mmenke@chromium.org>
Reviewed-by: Bence Béky <bnc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#652597}

net/http/http_stream_factory_job.cc

@@ -837,13 +837,13 @@ int HttpStreamFactory::Job::DoInitConnectionImpl() {
                       ptr_factory_.GetWeakPtr())
                 : base::RepeatingClosure();
 
-        bool is_first_request_for_session;
+        bool is_blocking_request_for_session;
         existing_spdy_session_ = session_->spdy_session_pool()->RequestSession(
             spdy_session_key_, enable_ip_based_pooling_,
             try_websocket_over_http2_, net_log_, resume_callback, this,
-            &spdy_session_request_, &is_first_request_for_session);
+            &spdy_session_request_, &is_blocking_request_for_session);
         if (!existing_spdy_session_ && should_throttle_connect &&
-            !is_first_request_for_session) {
+            !is_blocking_request_for_session) {
           net_log_.AddEvent(NetLogEventType::HTTP_STREAM_JOB_THROTTLED);
           next_state_ = STATE_INIT_CONNECTION;
           base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(

net/spdy/spdy_session_pool.cc

@@ -56,11 +56,13 @@ SpdySessionPool::SpdySessionRequest::SpdySessionRequest(
     const SpdySessionKey& key,
     bool enable_ip_based_pooling,
     bool is_websocket,
+    bool is_blocking_request_for_session,
     Delegate* delegate,
     SpdySessionPool* spdy_session_pool)
     : key_(key),
       enable_ip_based_pooling_(enable_ip_based_pooling),
       is_websocket_(is_websocket),
+      is_blocking_request_for_session_(is_blocking_request_for_session),
       delegate_(delegate),
       spdy_session_pool_(spdy_session_pool) {}
 
@@ -318,10 +320,10 @@ base::WeakPtr<SpdySession> SpdySessionPool::RequestSession(
     bool enable_ip_based_pooling,
     bool is_websocket,
     const NetLogWithSource& net_log,
-    base::RepeatingClosure on_request_destroyed_callback,
+    base::RepeatingClosure on_blocking_request_destroyed_callback,
     SpdySessionRequest::Delegate* delegate,
     std::unique_ptr<SpdySessionRequest>* spdy_session_request,
-    bool* is_first_request_for_session) {
+    bool* is_blocking_request_for_session) {
   DCHECK(delegate);
 
   base::WeakPtr<SpdySession> spdy_session =
@@ -329,19 +331,22 @@ base::WeakPtr<SpdySession> SpdySessionPool::RequestSession(
   if (spdy_session) {
     // This value doesn't really matter, but best to always populate it, for
     // consistency.
-    *is_first_request_for_session = true;
+    *is_blocking_request_for_session = true;
     return spdy_session;
   }
 
-  RequestSet* request_set = &spdy_session_request_map_[key];
-  *is_first_request_for_session = request_set->empty();
+  RequestInfoForKey* request_info = &spdy_session_request_map_[key];
+  *is_blocking_request_for_session = !request_info->has_blocking_request;
   *spdy_session_request = std::make_unique<SpdySessionRequest>(
-      key, enable_ip_based_pooling, is_websocket, delegate, this);
-  request_set->insert(spdy_session_request->get());
-
-  if (on_request_destroyed_callback && !*is_first_request_for_session) {
-    spdy_session_pending_request_map_[key].push_back(
-        on_request_destroyed_callback);
+      key, enable_ip_based_pooling, is_websocket,
+      *is_blocking_request_for_session, delegate, this);
+  request_info->request_set.insert(spdy_session_request->get());
+
+  if (*is_blocking_request_for_session) {
+    request_info->has_blocking_request = true;
+  } else if (on_blocking_request_destroyed_callback) {
+    request_info->deferred_callbacks.push_back(
+        on_blocking_request_destroyed_callback);
   }
   return nullptr;
 }
@@ -446,21 +451,21 @@ void SpdySessionPool::OnCertDBChanged() {
 void SpdySessionPool::RemoveRequestForSpdySession(SpdySessionRequest* request) {
   DCHECK_EQ(this, request->spdy_session_pool());
 
-  const SpdySessionKey& spdy_session_key = request->key();
-  // Resume all pending requests now that |request| is done/canceled.
-  if (spdy_session_pending_request_map_.find(spdy_session_key) !=
-      spdy_session_pending_request_map_.end()) {
+  auto iter = spdy_session_request_map_.find(request->key());
+  DCHECK(iter != spdy_session_request_map_.end());
+
+  // Resume all pending requests if it is the blocking request, which is either
+  // being canceled, or has completed.
+  if (request->is_blocking_request_for_session() &&
+      !iter->second.deferred_callbacks.empty()) {
     base::ThreadTaskRunnerHandle::Get()->PostTask(
         FROM_HERE,
         base::BindOnce(&SpdySessionPool::UpdatePendingRequests,
-                       weak_ptr_factory_.GetWeakPtr(), spdy_session_key));
+                       weak_ptr_factory_.GetWeakPtr(), request->key()));
   }
 
-  auto iter = spdy_session_request_map_.find(spdy_session_key);
-  DCHECK(iter != spdy_session_request_map_.end());
-  RequestSet& request_set = iter->second;
-  DCHECK(base::ContainsKey(request_set, request));
-  RemoveRequestInternal(iter, request_set.find(request));
+  DCHECK(base::ContainsKey(iter->second.request_set, request));
+  RemoveRequestInternal(iter, iter->second.request_set.find(request));
 }
 
 void SpdySessionPool::DumpMemoryStats(
@@ -510,6 +515,9 @@ void SpdySessionPool::DumpMemoryStats(
                   cert_size);
 }
 
+SpdySessionPool::RequestInfoForKey::RequestInfoForKey() = default;
+SpdySessionPool::RequestInfoForKey::~RequestInfoForKey() = default;
+
 bool SpdySessionPool::IsSessionAvailable(
     const base::WeakPtr<SpdySession>& session) const {
   for (auto it = available_sessions_.begin(); it != available_sessions_.end();
@@ -648,7 +656,7 @@ void SpdySessionPool::UpdatePendingRequests(const SpdySessionKey& key) {
       auto iter = spdy_session_request_map_.find(key);
       if (iter == spdy_session_request_map_.end())
         break;
-      RequestSet* request_set = &iter->second;
+      RequestSet* request_set = &iter->second.request_set;
       // Find a request that can use the socket, if any.
       RequestSet::iterator request;
       for (request = request_set->begin(); request != request_set->end();
@@ -671,19 +679,24 @@ void SpdySessionPool::UpdatePendingRequests(const SpdySessionKey& key) {
     }
   }
 
-  auto iter = spdy_session_pending_request_map_.find(key);
-  if (iter == spdy_session_pending_request_map_.end())
+  auto iter = spdy_session_request_map_.find(key);
+  if (iter == spdy_session_request_map_.end())
     return;
   // Remove all pending requests, if there are any. As a result, if one of these
   // callbacks triggers a new RequestSession() call,
-  // |is_first_request_for_session| will be true.
-  std::list<base::RepeatingClosure> pending_requests = std::move(iter->second);
-  spdy_session_pending_request_map_.erase(iter);
+  // |is_blocking_request_for_session| will be true.
+  std::list<base::RepeatingClosure> deferred_requests =
+      std::move(iter->second.deferred_callbacks);
 
-  // Resume any pending requests. This needs to be after the
+  // Delete the RequestMap if there are no SpdySessionRequests, and no deferred
+  // requests.
+  if (iter->second.request_set.empty())
+    spdy_session_request_map_.erase(iter);
+
+  // Resume any deferred requests. This needs to be after the
   // OnSpdySessionAvailable() calls, to prevent requests from calling into the
   // socket pools in cases where that's not necessary.
-  for (auto callback : pending_requests) {
+  for (auto callback : deferred_requests) {
     callback.Run();
   }
 }
@@ -692,9 +705,17 @@ void SpdySessionPool::RemoveRequestInternal(
     SpdySessionRequestMap::iterator request_map_iterator,
     RequestSet::iterator request_set_iterator) {
   SpdySessionRequest* request = *request_set_iterator;
-  request_map_iterator->second.erase(request_set_iterator);
-  if (request_map_iterator->second.empty())
+  request_map_iterator->second.request_set.erase(request_set_iterator);
+  if (request->is_blocking_request_for_session()) {
+    DCHECK(request_map_iterator->second.has_blocking_request);
+    request_map_iterator->second.has_blocking_request = false;
+  }
+
+  // If both lists of requests are empty, can now remove the entry from the map.
+  if (request_map_iterator->second.request_set.empty() &&
+      request_map_iterator->second.deferred_callbacks.empty()) {
     spdy_session_request_map_.erase(request_map_iterator);
+  }
   request->OnRemovedFromPool();
 }
 

net/spdy/spdy_session_pool.h

@@ -81,11 +81,11 @@ class NET_EXPORT SpdySessionPool
   // request must be destroyed before the SpdySessionPool is.
   //
   // TODO(mmenke): Remove the dependency on OnNewSpdySessionReady.
-  class SpdySessionRequest {
+  class NET_EXPORT_PRIVATE SpdySessionRequest {
    public:
     // Interface for watching for when a SpdySession with a provided key is
     // created.
-    class Delegate {
+    class NET_EXPORT_PRIVATE Delegate {
      public:
       Delegate();
       virtual ~Delegate();
@@ -102,6 +102,7 @@ class NET_EXPORT SpdySessionPool
     SpdySessionRequest(const SpdySessionKey& key,
                        bool enable_ip_based_pooling,
                        bool is_websocket,
+                       bool is_blocking_request_for_session,
                        Delegate* delegate,
                        SpdySessionPool* spdy_session_pool);
 
@@ -114,6 +115,9 @@ class NET_EXPORT SpdySessionPool
     const SpdySessionKey& key() const { return key_; }
     bool enable_ip_based_pooling() const { return enable_ip_based_pooling_; }
     bool is_websocket() const { return is_websocket_; }
+    bool is_blocking_request_for_session() const {
+      return is_blocking_request_for_session_;
+    }
     Delegate* delegate() { return delegate_; }
 
     // The associated SpdySessionPool, or nullptr if OnRemovedFromPool() has
@@ -124,6 +128,7 @@ class NET_EXPORT SpdySessionPool
     const SpdySessionKey key_;
     const bool enable_ip_based_pooling_;
     const bool is_websocket_;
+    const bool is_blocking_request_for_session_;
     Delegate* const delegate_;
     SpdySessionPool* spdy_session_pool_;
 
@@ -201,28 +206,33 @@ class NET_EXPORT SpdySessionPool
   // available through the creation of a new SpdySession (as opposed to by
   // creating an alias for an existing session with a new host).
   //
-  // |is_first_request_for_session| will be set to |true| if this is the first
-  // request for the session. If |on_request_destroyed_callback| is non-null and
-  // there is already at least one pending request for the session (i.e.,
-  // |is_first_request_for_session| is set to false), it will be invoked
-  // asynchronously whenever any matching |spdy_session_request| is destroyed or
-  // a matching SpdySession is created.
+  // |is_blocking_request_for_session| will be set to |true| if there is not
+  // another "blocking" request already pending. For example, the first request
+  // created will be considered "blocking", but subsequent requests will not as
+  // long as the "blocking" request is not destroyed.  Once the "blocking"
+  // request is destroyed, the next created request  will be marked "blocking".
   //
-  // |delegate|, |spdy_session_request|, and |is_first_request_for_session| must
-  // all be non-null.
+  //  If a request is created, that request is not the "blocking" request, and
+  //  |on_blocking_request_destroyed_callback| is non-null,
+  // then |on_blocking_request_destroyed_callback| will be invoked
+  // asynchronously when the "blocking" request is destroyed. The callback
+  // associated with the "blocking" request is never invoked.
+  //
+  // |delegate|, |spdy_session_request|, and |is_blocking_request_for_session|
+  // must all be non-null.
   //
   // TODO(mmenke): Merge this into FindAvailableSession().
-  // TODO(mmenke): Don't invoke |on_request_destroyed_callback| when all
-  // requests for a session have been successfully responded to.
+  // TODO(mmenke): Don't invoke |on_blocking_request_destroyed_callback| when
+  // all requests for a session have been successfully responded to.
   base::WeakPtr<SpdySession> RequestSession(
       const SpdySessionKey& key,
       bool enable_ip_based_pooling,
       bool is_websocket,
       const NetLogWithSource& net_log,
-      base::RepeatingClosure on_request_destroyed_callback,
+      base::RepeatingClosure on_blocking_request_destroyed_callback,
       SpdySessionRequest::Delegate* delegate,
       std::unique_ptr<SpdySessionRequest>* spdy_session_request,
-      bool* is_first_request_for_session);
+      bool* is_blocking_request_for_session);
 
   // Remove all mappings and aliases for the given session, which must
   // still be available. Except for in tests, this must be called by
@@ -296,14 +306,29 @@ class NET_EXPORT SpdySessionPool
  private:
   friend class SpdySessionPoolPeer;  // For testing.
 
-  typedef std::set<SpdySessionRequest*> RequestSet;
-  typedef std::map<SpdySessionKey, RequestSet> SpdySessionRequestMap;
   typedef std::set<SpdySession*> SessionSet;
   typedef std::vector<base::WeakPtr<SpdySession> > WeakSessionList;
-  typedef std::map<SpdySessionKey, base::WeakPtr<SpdySession> >
+  typedef std::map<SpdySessionKey, base::WeakPtr<SpdySession>>
       AvailableSessionMap;
   typedef std::multimap<IPEndPoint, SpdySessionKey> AliasMap;
 
+  typedef std::set<SpdySessionRequest*> RequestSet;
+  struct RequestInfoForKey {
+    RequestInfoForKey();
+    ~RequestInfoForKey();
+
+    // Whether one of the requests in |RequestSet| has its
+    // is_blocking_request_for_session() bit set.
+    bool has_blocking_request = false;
+
+    RequestSet request_set;
+
+    // Set of callbacks watching for the blocking request to be destroyed.
+    std::list<base::RepeatingClosure> deferred_callbacks;
+  };
+
+  typedef std::map<SpdySessionKey, RequestInfoForKey> SpdySessionRequestMap;
+
   // Removes |request| from |spdy_session_request_map_|.
   void RemoveRequestForSpdySession(SpdySessionRequest* request);
 
@@ -410,11 +435,7 @@ class NET_EXPORT SpdySessionPool
   // https://tools.ietf.org/html/draft-bishop-httpbis-grease-00.
   const base::Optional<GreasedHttp2Frame> greased_http2_frame_;
 
-  // TODO(xunjieli): Merge these two.
   SpdySessionRequestMap spdy_session_request_map_;
-  typedef std::map<SpdySessionKey, std::list<base::RepeatingClosure>>
-      SpdySessionPendingRequestMap;
-  SpdySessionPendingRequestMap spdy_session_pending_request_map_;
 
   TimeFunc time_func_;
   ServerPushDelegate* push_delegate_;

net/spdy/spdy_session_pool_unittest.cc

@@ -7,9 +7,11 @@
 #include <cstddef>
 #include <utility>
 
+#include "base/bind.h"
 #include "base/memory/ref_counted.h"
 #include "base/run_loop.h"
 #include "base/stl_util.h"
+#include "base/test/bind_test_util.h"
 #include "base/test/metrics/histogram_tester.h"
 #include "base/trace_event/memory_allocator_dump.h"
 #include "base/trace_event/process_memory_dump.h"
@@ -1146,4 +1148,195 @@ TEST_F(SpdySessionPoolTest, FindAvailableSessionForWebSocket) {
   EXPECT_TRUE(data.AllReadDataConsumed());
   EXPECT_TRUE(data.AllWriteDataConsumed());
 }
+
+class TestOnRequestDeletedCallback {
+ public:
+  TestOnRequestDeletedCallback() = default;
+  ~TestOnRequestDeletedCallback() = default;
+
+  base::RepeatingClosure Callback() {
+    return base::BindRepeating(&TestOnRequestDeletedCallback::OnRequestDeleted,
+                               base::Unretained(this));
+  }
+
+  bool invoked() const { return invoked_; }
+
+  void WaitUntilInvoked() { run_loop_.Run(); }
+
+  void SetRequestDeletedCallback(base::OnceClosure request_deleted_callback) {
+    DCHECK(!request_deleted_callback_);
+    request_deleted_callback_ = std::move(request_deleted_callback);
+  }
+
+ private:
+  void OnRequestDeleted() {
+    EXPECT_FALSE(invoked_);
+    invoked_ = true;
+    if (request_deleted_callback_)
+      std::move(request_deleted_callback_).Run();
+    run_loop_.Quit();
+  }
+
+  bool invoked_ = false;
+  base::RunLoop run_loop_;
+
+  base::OnceClosure request_deleted_callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestOnRequestDeletedCallback);
+};
+
+class TestRequestDelegate
+    : public SpdySessionPool::SpdySessionRequest::Delegate {
+ public:
+  TestRequestDelegate() = default;
+  ~TestRequestDelegate() override = default;
+
+  // SpdySessionPool::SpdySessionRequest::Delegate implementation:
+  void OnSpdySessionAvailable(
+      base::WeakPtr<SpdySession> spdy_session) override {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(TestRequestDelegate);
+};
+
+TEST_F(SpdySessionPoolTest, RequestSessionWithNoSessions) {
+  const SpdySessionKey kSessionKey(HostPortPair("foo.test", 443),
+                                   ProxyServer::Direct(), PRIVACY_MODE_DISABLED,
+                                   SpdySessionKey::IsProxySession::kFalse,
+                                   SocketTag());
+
+  CreateNetworkSession();
+
+  // First request. Its request deleted callback should never be invoked.
+  TestOnRequestDeletedCallback request_deleted_callback1;
+  TestRequestDelegate request_delegate1;
+  std::unique_ptr<SpdySessionPool::SpdySessionRequest> spdy_session_request1;
+  bool is_first_request_for_session;
+  EXPECT_FALSE(spdy_session_pool_->RequestSession(
+      kSessionKey, /* enable_ip_based_pooling = */ false,
+      /* is_websocket = */ false, NetLogWithSource(),
+      request_deleted_callback1.Callback(), &request_delegate1,
+      &spdy_session_request1, &is_first_request_for_session));
+  EXPECT_TRUE(is_first_request_for_session);
+
+  // Second request.
+  TestOnRequestDeletedCallback request_deleted_callback2;
+  TestRequestDelegate request_delegate2;
+  std::unique_ptr<SpdySessionPool::SpdySessionRequest> spdy_session_request2;
+  EXPECT_FALSE(spdy_session_pool_->RequestSession(
+      kSessionKey, /* enable_ip_based_pooling = */ false,
+      /* is_websocket = */ false, NetLogWithSource(),
+      request_deleted_callback2.Callback(), &request_delegate2,
+      &spdy_session_request2, &is_first_request_for_session));
+  EXPECT_FALSE(is_first_request_for_session);
+
+  // Third request.
+  TestOnRequestDeletedCallback request_deleted_callback3;
+  TestRequestDelegate request_delegate3;
+  std::unique_ptr<SpdySessionPool::SpdySessionRequest> spdy_session_request3;
+  EXPECT_FALSE(spdy_session_pool_->RequestSession(
+      kSessionKey, /* enable_ip_based_pooling = */ false,
+      /* is_websocket = */ false, NetLogWithSource(),
+      request_deleted_callback3.Callback(), &request_delegate3,
+      &spdy_session_request3, &is_first_request_for_session));
+  EXPECT_FALSE(is_first_request_for_session);
+
+  // Destroying the second request shouldn't cause anything to happen.
+  spdy_session_request2.reset();
+  base::RunLoop().RunUntilIdle();
+  EXPECT_FALSE(request_deleted_callback1.invoked());
+  EXPECT_FALSE(request_deleted_callback2.invoked());
+  EXPECT_FALSE(request_deleted_callback3.invoked());
+
+  // But destroying the first request should cause the second and third
+  // callbacks to be invoked.
+  spdy_session_request1.reset();
+  request_deleted_callback2.WaitUntilInvoked();
+  request_deleted_callback3.WaitUntilInvoked();
+  EXPECT_FALSE(request_deleted_callback1.invoked());
+
+  // Nothing should happen when the third request is destroyed.
+  spdy_session_request3.reset();
+  base::RunLoop().RunUntilIdle();
+  EXPECT_FALSE(request_deleted_callback1.invoked());
+}
+
+TEST_F(SpdySessionPoolTest, RequestSessionDuringNotification) {
+  const SpdySessionKey kSessionKey(HostPortPair("foo.test", 443),
+                                   ProxyServer::Direct(), PRIVACY_MODE_DISABLED,
+                                   SpdySessionKey::IsProxySession::kFalse,
+                                   SocketTag());
+
+  CreateNetworkSession();
+
+  // First request. Its request deleted callback should never be invoked.
+  TestOnRequestDeletedCallback request_deleted_callback1;
+  TestRequestDelegate request_delegate1;
+  std::unique_ptr<SpdySessionPool::SpdySessionRequest> spdy_session_request1;
+  bool is_first_request_for_session;
+  EXPECT_FALSE(spdy_session_pool_->RequestSession(
+      kSessionKey, /* enable_ip_based_pooling = */ false,
+      /* is_websocket = */ false, NetLogWithSource(),
+      request_deleted_callback1.Callback(), &request_delegate1,
+      &spdy_session_request1, &is_first_request_for_session));
+  EXPECT_TRUE(is_first_request_for_session);
+
+  // Second request.
+  TestOnRequestDeletedCallback request_deleted_callback2;
+  TestRequestDelegate request_delegate2;
+  std::unique_ptr<SpdySessionPool::SpdySessionRequest> spdy_session_request2;
+  EXPECT_FALSE(spdy_session_pool_->RequestSession(
+      kSessionKey, /* enable_ip_based_pooling = */ false,
+      /* is_websocket = */ false, NetLogWithSource(),
+      request_deleted_callback2.Callback(), &request_delegate2,
+      &spdy_session_request2, &is_first_request_for_session));
+  EXPECT_FALSE(is_first_request_for_session);
+
+  TestOnRequestDeletedCallback request_deleted_callback3;
+  TestRequestDelegate request_delegate3;
+  std::unique_ptr<SpdySessionPool::SpdySessionRequest> spdy_session_request3;
+  TestOnRequestDeletedCallback request_deleted_callback4;
+  TestRequestDelegate request_delegate4;
+  std::unique_ptr<SpdySessionPool::SpdySessionRequest> spdy_session_request4;
+  request_deleted_callback2.SetRequestDeletedCallback(
+      base::BindLambdaForTesting([&]() {
+        // Third request. It should again be marked as the first request for the
+        // session, since it's only created after the original two have been
+        // removed.
+        bool is_first_request_for_session;
+        EXPECT_FALSE(spdy_session_pool_->RequestSession(
+            kSessionKey, /* enable_ip_based_pooling = */ false,
+            /* is_websocket = */ false, NetLogWithSource(),
+            request_deleted_callback3.Callback(), &request_delegate3,
+            &spdy_session_request3, &is_first_request_for_session));
+        EXPECT_TRUE(is_first_request_for_session);
+
+        // Fourth request.
+        EXPECT_FALSE(spdy_session_pool_->RequestSession(
+            kSessionKey, /* enable_ip_based_pooling = */ false,
+            /* is_websocket = */ false, NetLogWithSource(),
+            request_deleted_callback4.Callback(), &request_delegate4,
+            &spdy_session_request4, &is_first_request_for_session));
+        EXPECT_FALSE(is_first_request_for_session);
+      }));
+
+  // Destroying the first request should cause the second callback to be
+  // invoked, and the third and fourth request to be made.
+  spdy_session_request1.reset();
+  request_deleted_callback2.WaitUntilInvoked();
+  base::RunLoop().RunUntilIdle();
+  EXPECT_FALSE(request_deleted_callback1.invoked());
+  EXPECT_FALSE(request_deleted_callback3.invoked());
+  EXPECT_FALSE(request_deleted_callback4.invoked());
+  EXPECT_TRUE(spdy_session_request3);
+  EXPECT_TRUE(spdy_session_request4);
+
+  // Destroying the third request should cause the fourth callback to be
+  // invoked.
+  spdy_session_request3.reset();
+  request_deleted_callback4.WaitUntilInvoked();
+  EXPECT_FALSE(request_deleted_callback1.invoked());
+  EXPECT_FALSE(request_deleted_callback3.invoked());
+}
+
 }  // namespace net