Revert 127717 - Revert 118788 - Revert 113405 - Revert 113305 - Revert 113300 - Revert 112134 - Revert 112130 - Close idle connections / SPDY sessions when needed

Due to the idle connection state being held by different socket pools, it's possible for one socket pool to hold an idle socket in a lower layer socket pool. From the lower level socket pool's perspective, the socket is being "actively" used. From the higher socket pool's (including SpdySession, which is more of a connection manager) perspective, the connection is idle and can be closed if we have hit a limit.

Normally this isn't a big deal, except when we have a lot of idle SPDY connections and are connecting via a proxy, so we have low connection limits through the proxy server. We address this problem by allowing lower-level socket pools to tell higher level socket pools to close a socket.

Fixed ASAN test failures by removing .Times(1) and .Times(2) from CloseMultipleIdleSocketsHeldByLayeredPoolWhenNeeded unittest (this removes the tests relying on the order of std::set in CloseOneIdleConnectionInLayeredPool). ASAN is prob
ably causing the memory allocator to allocate the pools differently. The std::set is ordered by LayeredPool* which is the address of the LayeredPool (willchan).

Added NET_EXPORT for layered_pool class defintion to fix windows shared compile.

BUG=62364, 92244, 109876, 110368

TEST=


Review URL: http://codereview.chromium.org/9667016

TBR=rch@chromium.org
Review URL: https://chromiumcodereview.appspot.com/9760002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@127730 0039d316-1c4b-4281-b951-d872f2087c98

12 files changed, 33 insertions, 486 deletions

diff --git a/net/socket/client_socket_handle.cc b/net/socket/client_socket_handle.cc
index af3c78a..8cc0e90 100644
--- a/net/socket/client_socket_handle.cc
+++ b/net/socket/client_socket_handle.cc
@@ -17,8 +17,6 @@ namespace net {
 
 ClientSocketHandle::ClientSocketHandle()
     : is_initialized_(false),
-      pool_(NULL),
-      layered_pool_(NULL),
       is_reused_(false),
       ALLOW_THIS_IN_INITIALIZER_LIST(callback_(
           base::Bind(&ClientSocketHandle::OnIOComplete,
@@ -54,10 +52,6 @@ void ClientSocketHandle::ResetInternal(bool cancel) {
   group_name_.clear();
   is_reused_ = false;
   user_callback_.Reset();
-  if (layered_pool_) {
-    pool_->RemoveLayeredPool(layered_pool_);
-    layered_pool_ = NULL;
-  }
   pool_ = NULL;
   idle_time_ = base::TimeDelta();
   init_time_ = base::TimeTicks();
@@ -81,19 +75,6 @@ LoadState ClientSocketHandle::GetLoadState() const {
   return pool_->GetLoadState(group_name_, this);
 }
 
-bool ClientSocketHandle::IsPoolStalled() const {
-  return pool_->IsStalled();
-}
-
-void ClientSocketHandle::AddLayeredPool(LayeredPool* layered_pool) {
-  CHECK(layered_pool);
-  CHECK(!layered_pool_);
-  if (pool_) {
-    pool_->AddLayeredPool(layered_pool);
-    layered_pool_ = layered_pool;
-  }
-}
-
 void ClientSocketHandle::OnIOComplete(int result) {
   CompletionCallback callback = user_callback_;
   user_callback_.Reset();
diff --git a/net/socket/client_socket_handle.h b/net/socket/client_socket_handle.h
index 0bdb8ac..0b9a652 100644
--- a/net/socket/client_socket_handle.h
+++ b/net/socket/client_socket_handle.h
@@ -92,10 +92,6 @@ class NET_EXPORT ClientSocketHandle {
   // initialized the ClientSocketHandle.
   LoadState GetLoadState() const;
 
-  bool IsPoolStalled() const;
-
-  void AddLayeredPool(LayeredPool* layered_pool);
-
   // Returns true when Init() has completed successfully.
   bool is_initialized() const { return is_initialized_; }
 
@@ -168,7 +164,6 @@ class NET_EXPORT ClientSocketHandle {
 
   bool is_initialized_;
   ClientSocketPool* pool_;
-  LayeredPool* layered_pool_;
   scoped_ptr<StreamSocket> socket_;
   std::string group_name_;
   bool is_reused_;
diff --git a/net/socket/client_socket_pool.h b/net/socket/client_socket_pool.h
index a13534a..92f0c413 100644
--- a/net/socket/client_socket_pool.h
+++ b/net/socket/client_socket_pool.h
@@ -29,17 +29,6 @@ class ClientSocketHandle;
 class ClientSocketPoolHistograms;
 class StreamSocket;
 
-// ClientSocketPools are layered. This defines an interface for lower level
-// socket pools to communicate with higher layer pools.
-class NET_EXPORT LayeredPool {
- public:
-  virtual ~LayeredPool() {}
-
-  // Instructs the LayeredPool to close an idle connection. Return true if one
-  // was closed.
-  virtual bool CloseOneIdleConnection() = 0;
-};
-
 // A ClientSocketPool is used to restrict the number of sockets open at a time.
 // It also maintains a list of idle persistent sockets.
 //
@@ -121,10 +110,6 @@ class NET_EXPORT ClientSocketPool {
   // the pool.  Does not flush any pools wrapped by |this|.
   virtual void Flush() = 0;
 
-  // Returns true if a there is currently a request blocked on the
-  // per-pool (not per-host) max socket limit.
-  virtual bool IsStalled() const = 0;
-
   // Called to close any idle connections held by the connection manager.
   virtual void CloseIdleSockets() = 0;
 
@@ -138,12 +123,6 @@ class NET_EXPORT ClientSocketPool {
   virtual LoadState GetLoadState(const std::string& group_name,
                                  const ClientSocketHandle* handle) const = 0;
 
-  // Adds a LayeredPool on top of |this|.
-  virtual void AddLayeredPool(LayeredPool* layered_pool) = 0;
-
-  // Removes a LayeredPool from |this|.
-  virtual void RemoveLayeredPool(LayeredPool* layered_pool) = 0;
-
   // Retrieves information on the current state of the pool as a
   // DictionaryValue.  Caller takes possession of the returned value.
   // If |include_nested_pools| is true, the states of any nested
diff --git a/net/socket/client_socket_pool_base.cc b/net/socket/client_socket_pool_base.cc
index b3417bf..d230ad4 100644
--- a/net/socket/client_socket_pool_base.cc
+++ b/net/socket/client_socket_pool_base.cc
@@ -207,7 +207,6 @@ ClientSocketPoolBaseHelper::~ClientSocketPoolBaseHelper() {
   DCHECK(group_map_.empty());
   DCHECK(pending_callback_map_.empty());
   DCHECK_EQ(0, connecting_socket_count_);
-  CHECK(higher_layer_pools_.empty());
 
   NetworkChangeNotifier::RemoveIPAddressObserver(this);
 }
@@ -239,18 +238,6 @@ ClientSocketPoolBaseHelper::RemoveRequestFromQueue(
   return req;
 }
 
-void ClientSocketPoolBaseHelper::AddLayeredPool(LayeredPool* pool) {
-  CHECK(pool);
-  CHECK(!ContainsKey(higher_layer_pools_, pool));
-  higher_layer_pools_.insert(pool);
-}
-
-void ClientSocketPoolBaseHelper::RemoveLayeredPool(LayeredPool* pool) {
-  CHECK(pool);
-  CHECK(ContainsKey(higher_layer_pools_, pool));
-  higher_layer_pools_.erase(pool);
-}
-
 int ClientSocketPoolBaseHelper::RequestSocket(
     const std::string& group_name,
     const Request* request) {
@@ -349,46 +336,26 @@ int ClientSocketPoolBaseHelper::RequestSocketInternal(
   // Can we make another active socket now?
   if (!group->HasAvailableSocketSlot(max_sockets_per_group_) &&
       !request->ignore_limits()) {
-    // TODO(willchan): Consider whether or not we need to close a socket in a
-    // higher layered group. I don't think this makes sense since we would just
-    // reuse that socket then if we needed one and wouldn't make it down to this
-    // layer.
     request->net_log().AddEvent(
         NetLog::TYPE_SOCKET_POOL_STALLED_MAX_SOCKETS_PER_GROUP, NULL);
     return ERR_IO_PENDING;
   }
 
   if (ReachedMaxSocketsLimit() && !request->ignore_limits()) {
-    // NOTE(mmenke):  Wonder if we really need different code for each case
-    // here.  Only reason for them now seems to be preconnects.
     if (idle_socket_count() > 0) {
-      // There's an idle socket in this pool. Either that's because there's
-      // still one in this group, but we got here due to preconnecting bypassing
-      // idle sockets, or because there's an idle socket in another group.
       bool closed = CloseOneIdleSocketExceptInGroup(group);
       if (preconnecting && !closed)
         return ERR_PRECONNECT_MAX_SOCKET_LIMIT;
     } else {
-      do {
-        if (!CloseOneIdleConnectionInLayeredPool()) {
-          // We could check if we really have a stalled group here, but it
-          // requires a scan of all groups, so just flip a flag here, and do
-          // the check later.
-          request->net_log().AddEvent(
-              NetLog::TYPE_SOCKET_POOL_STALLED_MAX_SOCKETS, NULL);
-          return ERR_IO_PENDING;
-        }
-      } while (ReachedMaxSocketsLimit());
-
-      // It is possible that CloseOneIdleConnectionInLayeredPool() has deleted
-      // our Group (see http://crbug.com/109876), so look it up again
-      // to be safe.
-      group = GetOrCreateGroup(group_name);
+      // We could check if we really have a stalled group here, but it requires
+      // a scan of all groups, so just flip a flag here, and do the check later.
+      request->net_log().AddEvent(
+          NetLog::TYPE_SOCKET_POOL_STALLED_MAX_SOCKETS, NULL);
+      return ERR_IO_PENDING;
     }
   }
 
-  // We couldn't find a socket to reuse, and there's space to allocate one,
-  // so allocate and connect a new one.
+  // We couldn't find a socket to reuse, so allocate and connect a new one.
   scoped_ptr<ConnectJob> connect_job(
       connect_job_factory_->NewConnectJob(group_name, *request, this));
 
@@ -650,8 +617,7 @@ DictionaryValue* ClientSocketPoolBaseHelper::GetInfoAsValue(
     group_dict->Set("connect_jobs", connect_jobs_list);
 
     group_dict->SetBoolean("is_stalled",
-                           group->IsStalledOnPoolMaxSockets(
-                               max_sockets_per_group_));
+                           group->IsStalled(max_sockets_per_group_));
     group_dict->SetBoolean("has_backup_job", group->HasBackupJob());
 
     all_groups_dict->SetWithoutPathExpansion(it->first, group_dict);
@@ -826,22 +792,18 @@ void ClientSocketPoolBaseHelper::CheckForStalledSocketGroups() {
 // are not at the |max_sockets_per_group_| limit. Note: for requests with
 // the same priority, the winner is based on group hash ordering (and not
 // insertion order).
-bool ClientSocketPoolBaseHelper::FindTopStalledGroup(
-    Group** group,
-    std::string* group_name) const {
-  CHECK((group && group_name) || (!group && !group_name));
+bool ClientSocketPoolBaseHelper::FindTopStalledGroup(Group** group,
+                                                     std::string* group_name) {
   Group* top_group = NULL;
   const std::string* top_group_name = NULL;
   bool has_stalled_group = false;
-  for (GroupMap::const_iterator i = group_map_.begin();
+  for (GroupMap::iterator i = group_map_.begin();
        i != group_map_.end(); ++i) {
     Group* curr_group = i->second;
     const RequestQueue& queue = curr_group->pending_requests();
     if (queue.empty())
       continue;
-    if (curr_group->IsStalledOnPoolMaxSockets(max_sockets_per_group_)) {
-      if (!group)
-        return true;
+    if (curr_group->IsStalled(max_sockets_per_group_)) {
       has_stalled_group = true;
       bool has_higher_priority = !top_group ||
           curr_group->TopPendingPriority() < top_group->TopPendingPriority();
@@ -853,11 +815,8 @@ bool ClientSocketPoolBaseHelper::FindTopStalledGroup(
   }
 
   if (top_group) {
-    CHECK(group);
     *group = top_group;
     *group_name = *top_group_name;
-  } else {
-    CHECK(!has_stalled_group);
   }
   return has_stalled_group;
 }
@@ -930,25 +889,6 @@ void ClientSocketPoolBaseHelper::Flush() {
   AbortAllRequests();
 }
 
-bool ClientSocketPoolBaseHelper::IsStalled() const {
-  // If we are not using |max_sockets_|, then clearly we are not stalled
-  if ((handed_out_socket_count_ + connecting_socket_count_) < max_sockets_)
-    return false;
-  // So in order to be stalled we need to be using |max_sockets_| AND
-  // we need to have a request that is actually stalled on the global
-  // socket limit.  To find such a request, we look for a group that
-  // a has more requests that jobs AND where the number of jobs is less
-  // than |max_sockets_per_group_|.  (If the number of jobs is equal to
-  // |max_sockets_per_group_|, then the request is stalled on the group,
-  // which does not count.)
-  for (GroupMap::const_iterator it = group_map_.begin();
-       it != group_map_.end(); it++) {
-    if (it->second->IsStalledOnPoolMaxSockets(max_sockets_per_group_))
-      return true;
-  }
-  return false;
-}
-
 void ClientSocketPoolBaseHelper::RemoveConnectJob(ConnectJob* job,
                                                   Group* group) {
   CHECK_GT(connecting_socket_count_, 0);
@@ -1085,10 +1025,8 @@ bool ClientSocketPoolBaseHelper::ReachedMaxSocketsLimit() const {
   return true;
 }
 
-bool ClientSocketPoolBaseHelper::CloseOneIdleSocket() {
-  if (idle_socket_count() == 0)
-    return false;
-  return CloseOneIdleSocketExceptInGroup(NULL);
+void ClientSocketPoolBaseHelper::CloseOneIdleSocket() {
+  CloseOneIdleSocketExceptInGroup(NULL);
 }
 
 bool ClientSocketPoolBaseHelper::CloseOneIdleSocketExceptInGroup(
@@ -1112,18 +1050,9 @@ bool ClientSocketPoolBaseHelper::CloseOneIdleSocketExceptInGroup(
     }
   }
 
-  return false;
-}
+  if (!exception_group)
+    LOG(DFATAL) << "No idle socket found to close!.";
 
-bool ClientSocketPoolBaseHelper::CloseOneIdleConnectionInLayeredPool() {
-  // This pool doesn't have any idle sockets. It's possible that a pool at a
-  // higher layer is holding one of this sockets active, but it's actually idle.
-  // Query the higher layers.
-  for (std::set<LayeredPool*>::const_iterator it = higher_layer_pools_.begin();
-       it != higher_layer_pools_.end(); ++it) {
-    if ((*it)->CloseOneIdleConnection())
-      return true;
-  }
   return false;
 }
 
diff --git a/net/socket/client_socket_pool_base.h b/net/socket/client_socket_pool_base.h
index 832c166..f550e42 100644
--- a/net/socket/client_socket_pool_base.h
+++ b/net/socket/client_socket_pool_base.h
@@ -28,7 +28,6 @@
 #include <map>
 #include <set>
 #include <string>
-#include <vector>
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
@@ -240,11 +239,6 @@ class NET_EXPORT_PRIVATE ClientSocketPoolBaseHelper
 
   virtual ~ClientSocketPoolBaseHelper();
 
-  // Adds/Removes layered pools. It is expected in the destructor that no
-  // layered pools remain.
-  void AddLayeredPool(LayeredPool* pool);
-  void RemoveLayeredPool(LayeredPool* pool);
-
   // See ClientSocketPool::RequestSocket for documentation on this function.
   // ClientSocketPoolBaseHelper takes ownership of |request|, which must be
   // heap allocated.
@@ -267,9 +261,6 @@ class NET_EXPORT_PRIVATE ClientSocketPoolBaseHelper
   // See ClientSocketPool::Flush for documentation on this function.
   void Flush();
 
-  // See ClientSocketPool::IsStalled for documentation on this function.
-  bool IsStalled() const;
-
   // See ClientSocketPool::CloseIdleSockets for documentation on this function.
   void CloseIdleSockets();
 
@@ -315,16 +306,6 @@ class NET_EXPORT_PRIVATE ClientSocketPoolBaseHelper
   // sockets that timed out or can't be reused.  Made public for testing.
   void CleanupIdleSockets(bool force);
 
-  // Closes one idle socket.  Picks the first one encountered.
-  // TODO(willchan): Consider a better algorithm for doing this.  Perhaps we
-  // should keep an ordered list of idle sockets, and close them in order.
-  // Requires maintaining more state.  It's not clear if it's worth it since
-  // I'm not sure if we hit this situation often.
-  bool CloseOneIdleSocket();
-
-  // Checks layered pools to see if they can close an idle connection.
-  bool CloseOneIdleConnectionInLayeredPool();
-
   // See ClientSocketPool::GetInfoAsValue for documentation on this function.
   base::DictionaryValue* GetInfoAsValue(const std::string& name,
                                         const std::string& type) const;
@@ -390,7 +371,7 @@ class NET_EXPORT_PRIVATE ClientSocketPoolBaseHelper
           static_cast<int>(idle_sockets_.size());
     }
 
-    bool IsStalledOnPoolMaxSockets(int max_sockets_per_group) const {
+    bool IsStalled(int max_sockets_per_group) const {
       return HasAvailableSocketSlot(max_sockets_per_group) &&
           pending_requests_.size() > jobs_.size();
     }
@@ -476,9 +457,9 @@ class NET_EXPORT_PRIVATE ClientSocketPoolBaseHelper
 
   // Scans the group map for groups which have an available socket slot and
   // at least one pending request. Returns true if any groups are stalled, and
-  // if so (and if both |group| and |group_name| are not NULL), fills |group|
-  // and |group_name| with data of the stalled group having highest priority.
-  bool FindTopStalledGroup(Group** group, std::string* group_name) const;
+  // if so, fills |group| and |group_name| with data of the stalled group
+  // having highest priority.
+  bool FindTopStalledGroup(Group** group, std::string* group_name);
 
   // Called when timer_ fires.  This method scans the idle sockets removing
   // sockets that timed out or can't be reused.
@@ -530,6 +511,13 @@ class NET_EXPORT_PRIVATE ClientSocketPoolBaseHelper
   static void LogBoundConnectJobToRequest(
       const NetLog::Source& connect_job_source, const Request* request);
 
+  // Closes one idle socket.  Picks the first one encountered.
+  // TODO(willchan): Consider a better algorithm for doing this.  Perhaps we
+  // should keep an ordered list of idle sockets, and close them in order.
+  // Requires maintaining more state.  It's not clear if it's worth it since
+  // I'm not sure if we hit this situation often.
+  void CloseOneIdleSocket();
+
   // Same as CloseOneIdleSocket() except it won't close an idle socket in
   // |group|.  If |group| is NULL, it is ignored.  Returns true if it closed a
   // socket.
@@ -594,8 +582,6 @@ class NET_EXPORT_PRIVATE ClientSocketPoolBaseHelper
   // make sure that they are discarded rather than reused.
   int pool_generation_number_;
 
-  std::set<LayeredPool*> higher_layer_pools_;
-
   base::WeakPtrFactory<ClientSocketPoolBaseHelper> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ClientSocketPoolBaseHelper);
@@ -662,13 +648,6 @@ class ClientSocketPoolBase {
   virtual ~ClientSocketPoolBase() {}
 
   // These member functions simply forward to ClientSocketPoolBaseHelper.
-  void AddLayeredPool(LayeredPool* pool) {
-    helper_.AddLayeredPool(pool);
-  }
-
-  void RemoveLayeredPool(LayeredPool* pool) {
-    helper_.RemoveLayeredPool(pool);
-  }
 
   // RequestSocket bundles up the parameters into a Request and then forwards to
   // ClientSocketPoolBaseHelper::RequestSocket().
@@ -713,10 +692,6 @@ class ClientSocketPoolBase {
     return helper_.ReleaseSocket(group_name, socket, id);
   }
 
-  void Flush() { helper_.Flush(); }
-
-  bool IsStalled() const { return helper_.IsStalled(); }
-
   void CloseIdleSockets() { return helper_.CloseIdleSockets(); }
 
   int idle_socket_count() const { return helper_.idle_socket_count(); }
@@ -765,11 +740,7 @@ class ClientSocketPoolBase {
 
   void EnableConnectBackupJobs() { helper_.EnableConnectBackupJobs(); }
 
-  bool CloseOneIdleSocket() { return helper_.CloseOneIdleSocket(); }
-
-  bool CloseOneIdleConnectionInLayeredPool() {
-    return helper_.CloseOneIdleConnectionInLayeredPool();
-  }
+  void Flush() { helper_.Flush(); }
 
  private:
   // This adaptor class exists to bridge the
diff --git a/net/socket/client_socket_pool_base_unittest.cc b/net/socket/client_socket_pool_base_unittest.cc
index 6c692fe..b1c1a99 100644
--- a/net/socket/client_socket_pool_base_unittest.cc
+++ b/net/socket/client_socket_pool_base_unittest.cc
@@ -4,8 +4,6 @@
 
 #include "net/socket/client_socket_pool_base.h"
 
-#include <vector>
-
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/callback.h"
@@ -30,12 +28,8 @@
 #include "net/socket/socket_test_util.h"
 #include "net/socket/ssl_host_info.h"
 #include "net/socket/stream_socket.h"
-#include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-using ::testing::Invoke;
-using ::testing::Return;
-
 namespace net {
 
 namespace {
@@ -46,18 +40,10 @@ const net::RequestPriority kDefaultPriority = MEDIUM;
 
 class TestSocketParams : public base::RefCounted<TestSocketParams> {
  public:
-  TestSocketParams() : ignore_limits_(false) {}
-
-  void set_ignore_limits(bool ignore_limits) {
-    ignore_limits_ = ignore_limits;
-  }
-  bool ignore_limits() { return ignore_limits_; }
-
+  bool ignore_limits() { return false; }
  private:
   friend class base::RefCounted<TestSocketParams>;
   ~TestSocketParams() {}
-
-  bool ignore_limits_;
 };
 typedef ClientSocketPoolBase<TestSocketParams> TestClientSocketPoolBase;
 
@@ -369,18 +355,12 @@ class TestConnectJobFactory
  public:
   explicit TestConnectJobFactory(MockClientSocketFactory* client_socket_factory)
       : job_type_(TestConnectJob::kMockJob),
-        job_types_(NULL),
         client_socket_factory_(client_socket_factory) {}
 
   virtual ~TestConnectJobFactory() {}
 
   void set_job_type(TestConnectJob::JobType job_type) { job_type_ = job_type; }
 
-  void set_job_types(std::list<TestConnectJob::JobType>* job_types) {
-    job_types_ = job_types;
-    CHECK(!job_types_->empty());
-  }
-
   void set_timeout_duration(base::TimeDelta timeout_duration) {
     timeout_duration_ = timeout_duration;
   }
@@ -391,13 +371,7 @@ class TestConnectJobFactory
       const std::string& group_name,
       const TestClientSocketPoolBase::Request& request,
       ConnectJob::Delegate* delegate) const {
-    EXPECT_TRUE(!job_types_ || !job_types_->empty());
-    TestConnectJob::JobType job_type = job_type_;
-    if (job_types_ && !job_types_->empty()) {
-      job_type = job_types_->front();
-      job_types_->pop_front();
-    }
-    return new TestConnectJob(job_type,
+    return new TestConnectJob(job_type_,
                               group_name,
                               request,
                               timeout_duration_,
@@ -412,7 +386,6 @@ class TestConnectJobFactory
 
  private:
   TestConnectJob::JobType job_type_;
-  std::list<TestConnectJob::JobType>* job_types_;
   base::TimeDelta timeout_duration_;
   MockClientSocketFactory* const client_socket_factory_;
 
@@ -474,10 +447,6 @@ class TestClientSocketPool : public ClientSocketPool {
     base_.Flush();
   }
 
-  virtual bool IsStalled() const OVERRIDE {
-    return base_.IsStalled();
-  }
-
   virtual void CloseIdleSockets() OVERRIDE {
     base_.CloseIdleSockets();
   }
@@ -497,14 +466,6 @@ class TestClientSocketPool : public ClientSocketPool {
     return base_.GetLoadState(group_name, handle);
   }
 
-  virtual void AddLayeredPool(LayeredPool* pool) OVERRIDE {
-    base_.AddLayeredPool(pool);
-  }
-
-  virtual void RemoveLayeredPool(LayeredPool* pool) OVERRIDE {
-    base_.RemoveLayeredPool(pool);
-  }
-
   virtual DictionaryValue* GetInfoAsValue(
       const std::string& name,
       const std::string& type,
@@ -538,10 +499,6 @@ class TestClientSocketPool : public ClientSocketPool {
 
   void EnableConnectBackupJobs() { base_.EnableConnectBackupJobs(); }
 
-  bool CloseOneIdleConnectionInLayeredPool() {
-    return base_.CloseOneIdleConnectionInLayeredPool();
-  }
-
  private:
   TestClientSocketPoolBase base_;
 
@@ -1207,7 +1164,6 @@ TEST_F(ClientSocketPoolBaseTest, WaitForStalledSocketAtSocketLimit) {
   ClientSocketHandle stalled_handle;
   TestCompletionCallback callback;
   {
-    EXPECT_FALSE(pool_->IsStalled());
     ClientSocketHandle handles[kDefaultMaxSockets];
     for (int i = 0; i < kDefaultMaxSockets; ++i) {
       TestCompletionCallback callback;
@@ -1222,7 +1178,6 @@ TEST_F(ClientSocketPoolBaseTest, WaitForStalledSocketAtSocketLimit) {
 
     EXPECT_EQ(kDefaultMaxSockets, client_socket_factory_.allocation_count());
     EXPECT_EQ(0, pool_->IdleSocketCount());
-    EXPECT_FALSE(pool_->IsStalled());
 
     // Now we will hit the socket limit.
     EXPECT_EQ(ERR_IO_PENDING, stalled_handle.Init("foo",
@@ -1231,7 +1186,6 @@ TEST_F(ClientSocketPoolBaseTest, WaitForStalledSocketAtSocketLimit) {
                                                   callback.callback(),
                                                   pool_.get(),
                                                   BoundNetLog()));
-    EXPECT_TRUE(pool_->IsStalled());
 
     // Dropping out of scope will close all handles and return them to idle.
   }
@@ -2051,9 +2005,9 @@ TEST_F(ClientSocketPoolBaseTest, DisableCleanupTimer) {
   EXPECT_EQ(1, handle2.socket()->Write(NULL, 1, CompletionCallback()));
   handle2.Reset();
 
-  // The idle socket timeout value was set to 10 milliseconds. Wait 100
+  // The idle socket timeout value was set to 10 milliseconds. Wait 20
   // milliseconds so the sockets timeout.
-  base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(100));
+  base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(20));
   MessageLoop::current()->RunAllPending();
 
   ASSERT_EQ(2, pool_->IdleSocketCount());
@@ -3085,7 +3039,6 @@ TEST_F(ClientSocketPoolBaseTest, RequestSocketsHitMaxSocketLimit) {
 
   ASSERT_TRUE(pool_->HasGroup("a"));
   EXPECT_EQ(kDefaultMaxSockets - 1, pool_->NumConnectJobsInGroup("a"));
-  EXPECT_FALSE(pool_->IsStalled());
 
   ASSERT_FALSE(pool_->HasGroup("b"));
 
@@ -3094,7 +3047,6 @@ TEST_F(ClientSocketPoolBaseTest, RequestSocketsHitMaxSocketLimit) {
 
   ASSERT_TRUE(pool_->HasGroup("b"));
   EXPECT_EQ(1, pool_->NumConnectJobsInGroup("b"));
-  EXPECT_FALSE(pool_->IsStalled());
 }
 
 TEST_F(ClientSocketPoolBaseTest, RequestSocketsCountIdleSockets) {
@@ -3413,173 +3365,6 @@ TEST_F(ClientSocketPoolBaseTest, PreconnectWithBackupJob) {
   EXPECT_EQ(1, pool_->NumActiveSocketsInGroup("a"));
 }
 
-class MockLayeredPool : public LayeredPool {
- public:
-  MockLayeredPool(TestClientSocketPool* pool,
-                  const std::string& group_name)
-      : pool_(pool),
-        params_(new TestSocketParams),
-        group_name_(group_name),
-        can_release_connection_(true) {
-    pool_->AddLayeredPool(this);
-  }
-
-  ~MockLayeredPool() {
-    pool_->RemoveLayeredPool(this);
-  }
-
-  int RequestSocket(TestClientSocketPool* pool) {
-    return handle_.Init(group_name_, params_, kDefaultPriority,
-                        callback_.callback(), pool, BoundNetLog());
-  }
-
-  int RequestSocketWithoutLimits(TestClientSocketPool* pool) {
-    params_->set_ignore_limits(true);
-    return handle_.Init(group_name_, params_, kDefaultPriority,
-                        callback_.callback(), pool, BoundNetLog());
-  }
-
-  bool ReleaseOneConnection() {
-    if (!handle_.is_initialized() || !can_release_connection_) {
-      return false;
-    }
-    handle_.socket()->Disconnect();
-    handle_.Reset();
-    return true;
-  }
-
-  void set_can_release_connection(bool can_release_connection) {
-    can_release_connection_ = can_release_connection;
-  }
-
-  MOCK_METHOD0(CloseOneIdleConnection, bool());
-
- private:
-  TestClientSocketPool* const pool_;
-  scoped_refptr<TestSocketParams> params_;
-  ClientSocketHandle handle_;
-  TestCompletionCallback callback_;
-  const std::string group_name_;
-  bool can_release_connection_;
-};
-
-TEST_F(ClientSocketPoolBaseTest, FailToCloseIdleSocketsNotHeldByLayeredPool) {
-  CreatePool(kDefaultMaxSockets, kDefaultMaxSocketsPerGroup);
-  connect_job_factory_->set_job_type(TestConnectJob::kMockJob);
-
-  MockLayeredPool mock_layered_pool(pool_.get(), "foo");
-  EXPECT_EQ(OK, mock_layered_pool.RequestSocket(pool_.get()));
-  EXPECT_CALL(mock_layered_pool, CloseOneIdleConnection())
-      .WillOnce(Return(false));
-  EXPECT_FALSE(pool_->CloseOneIdleConnectionInLayeredPool());
-}
-
-TEST_F(ClientSocketPoolBaseTest, ForciblyCloseIdleSocketsHeldByLayeredPool) {
-  CreatePool(kDefaultMaxSockets, kDefaultMaxSocketsPerGroup);
-  connect_job_factory_->set_job_type(TestConnectJob::kMockJob);
-
-  MockLayeredPool mock_layered_pool(pool_.get(), "foo");
-  EXPECT_EQ(OK, mock_layered_pool.RequestSocket(pool_.get()));
-  EXPECT_CALL(mock_layered_pool, CloseOneIdleConnection())
-      .WillOnce(Invoke(&mock_layered_pool,
-                       &MockLayeredPool::ReleaseOneConnection));
-  EXPECT_TRUE(pool_->CloseOneIdleConnectionInLayeredPool());
-}
-
-// This test exercises the codepath which caused http://crbug.com/109876
-TEST_F(ClientSocketPoolBaseTest,
-       CloseIdleSocketsHeldByLayeredPoolInSameGroupWhenNeeded) {
-  CreatePool(2, 2);
-  std::list<TestConnectJob::JobType> job_types;
-  job_types.push_back(TestConnectJob::kMockJob);
-  job_types.push_back(TestConnectJob::kMockJob);
-  job_types.push_back(TestConnectJob::kMockFailingJob);
-  job_types.push_back(TestConnectJob::kMockJob);
-  connect_job_factory_->set_job_types(&job_types);
-
-  ClientSocketHandle handle1;
-  TestCompletionCallback callback1;
-  EXPECT_EQ(OK, handle1.Init("group1",
-                             params_,
-                             kDefaultPriority,
-                             callback1.callback(),
-                             pool_.get(),
-                             BoundNetLog()));
-
-  MockLayeredPool mock_layered_pool(pool_.get(), "group2");
-  EXPECT_EQ(OK, mock_layered_pool.RequestSocket(pool_.get()));
-  EXPECT_CALL(mock_layered_pool, CloseOneIdleConnection())
-      .WillRepeatedly(Invoke(&mock_layered_pool,
-                             &MockLayeredPool::ReleaseOneConnection));
-  mock_layered_pool.set_can_release_connection(false);
-
-  // This connection attempt will fail when the next request causes the
-  // MockLayeredPool to delete the socket it's holding.  This request is
-  // needed to trigger the destruction of the "group2" Group.
-  ClientSocketHandle handle3;
-  TestCompletionCallback callback3;
-  EXPECT_EQ(ERR_IO_PENDING, handle3.Init("group2",
-                                         params_,
-                                         kDefaultPriority,
-                                         callback3.callback(),
-                                         pool_.get(),
-                                         BoundNetLog()));
-
-  mock_layered_pool.set_can_release_connection(true);
-  ClientSocketHandle handle4;
-  TestCompletionCallback callback4;
-  EXPECT_EQ(OK, handle4.Init("group2",
-                             params_,
-                             kDefaultPriority,
-                             callback4.callback(),
-                             pool_.get(),
-                             BoundNetLog()));
-}
-
-TEST_F(ClientSocketPoolBaseTest, CloseIdleSocketsHeldByLayeredPoolWhenNeeded) {
-  CreatePool(1, 1);
-  connect_job_factory_->set_job_type(TestConnectJob::kMockJob);
-
-  MockLayeredPool mock_layered_pool(pool_.get(), "foo");
-  EXPECT_EQ(OK, mock_layered_pool.RequestSocket(pool_.get()));
-  EXPECT_CALL(mock_layered_pool, CloseOneIdleConnection())
-      .WillOnce(Invoke(&mock_layered_pool,
-                       &MockLayeredPool::ReleaseOneConnection));
-  ClientSocketHandle handle;
-  TestCompletionCallback callback;
-  EXPECT_EQ(OK, handle.Init("a",
-                            params_,
-                            kDefaultPriority,
-                            callback.callback(),
-                            pool_.get(),
-                            BoundNetLog()));
-}
-
-TEST_F(ClientSocketPoolBaseTest,
-       CloseMultipleIdleSocketsHeldByLayeredPoolWhenNeeded) {
-  CreatePool(1, 1);
-  connect_job_factory_->set_job_type(TestConnectJob::kMockJob);
-
-  MockLayeredPool mock_layered_pool1(pool_.get(), "foo");
-  EXPECT_EQ(OK, mock_layered_pool1.RequestSocket(pool_.get()));
-  EXPECT_CALL(mock_layered_pool1, CloseOneIdleConnection())
-      .WillRepeatedly(Invoke(&mock_layered_pool1,
-                             &MockLayeredPool::ReleaseOneConnection));
-  MockLayeredPool mock_layered_pool2(pool_.get(), "bar");
-  EXPECT_EQ(OK, mock_layered_pool2.RequestSocketWithoutLimits(pool_.get()));
-  EXPECT_CALL(mock_layered_pool2, CloseOneIdleConnection())
-      .WillRepeatedly(Invoke(&mock_layered_pool2,
-                             &MockLayeredPool::ReleaseOneConnection));
-  ClientSocketHandle handle;
-  TestCompletionCallback callback;
-  EXPECT_EQ(OK, handle.Init("a",
-                            params_,
-                            kDefaultPriority,
-                            callback.callback(),
-                            pool_.get(),
-                            BoundNetLog()));
-}
-
 }  // namespace
 
 }  // namespace net
diff --git a/net/socket/socks_client_socket_pool.cc b/net/socket/socks_client_socket_pool.cc
index a7c7ecb..ae963bf 100644
--- a/net/socket/socks_client_socket_pool.cc
+++ b/net/socket/socks_client_socket_pool.cc
@@ -199,16 +199,9 @@ SOCKSClientSocketPool::SOCKSClientSocketPool(
             new SOCKSConnectJobFactory(transport_pool,
                                        host_resolver,
                                        net_log)) {
-  // We should always have a |transport_pool_| except in unit tests.
-  if (transport_pool_)
-    transport_pool_->AddLayeredPool(this);
 }
 
-SOCKSClientSocketPool::~SOCKSClientSocketPool() {
-  // We should always have a |transport_pool_| except in unit tests.
-  if (transport_pool_)
-    transport_pool_->RemoveLayeredPool(this);
-}
+SOCKSClientSocketPool::~SOCKSClientSocketPool() {}
 
 int SOCKSClientSocketPool::RequestSocket(
     const std::string& group_name, const void* socket_params,
@@ -246,10 +239,6 @@ void SOCKSClientSocketPool::Flush() {
   base_.Flush();
 }
 
-bool SOCKSClientSocketPool::IsStalled() const {
-  return base_.IsStalled() || transport_pool_->IsStalled();
-}
-
 void SOCKSClientSocketPool::CloseIdleSockets() {
   base_.CloseIdleSockets();
 }
@@ -268,14 +257,6 @@ LoadState SOCKSClientSocketPool::GetLoadState(
   return base_.GetLoadState(group_name, handle);
 }
 
-void SOCKSClientSocketPool::AddLayeredPool(LayeredPool* layered_pool) {
-  base_.AddLayeredPool(layered_pool);
-}
-
-void SOCKSClientSocketPool::RemoveLayeredPool(LayeredPool* layered_pool) {
-  base_.RemoveLayeredPool(layered_pool);
-}
-
 DictionaryValue* SOCKSClientSocketPool::GetInfoAsValue(
     const std::string& name,
     const std::string& type,
@@ -299,10 +280,4 @@ ClientSocketPoolHistograms* SOCKSClientSocketPool::histograms() const {
   return base_.histograms();
 };
 
-bool SOCKSClientSocketPool::CloseOneIdleConnection() {
-  if (base_.CloseOneIdleSocket())
-    return true;
-  return base_.CloseOneIdleConnectionInLayeredPool();
-}
-
 }  // namespace net
diff --git a/net/socket/socks_client_socket_pool.h b/net/socket/socks_client_socket_pool.h
index 8583d96..3fc7df6 100644
--- a/net/socket/socks_client_socket_pool.h
+++ b/net/socket/socks_client_socket_pool.h
@@ -105,8 +105,7 @@ class SOCKSConnectJob : public ConnectJob {
   DISALLOW_COPY_AND_ASSIGN(SOCKSConnectJob);
 };
 
-class NET_EXPORT_PRIVATE SOCKSClientSocketPool
-    : public ClientSocketPool, public LayeredPool {
+class NET_EXPORT_PRIVATE SOCKSClientSocketPool : public ClientSocketPool {
  public:
   SOCKSClientSocketPool(
       int max_sockets,
@@ -140,8 +139,6 @@ class NET_EXPORT_PRIVATE SOCKSClientSocketPool
 
   virtual void Flush() OVERRIDE;
 
-  virtual bool IsStalled() const OVERRIDE;
-
   virtual void CloseIdleSockets() OVERRIDE;
 
   virtual int IdleSocketCount() const OVERRIDE;
@@ -153,10 +150,6 @@ class NET_EXPORT_PRIVATE SOCKSClientSocketPool
       const std::string& group_name,
       const ClientSocketHandle* handle) const OVERRIDE;
 
-  virtual void AddLayeredPool(LayeredPool* layered_pool) OVERRIDE;
-
-  virtual void RemoveLayeredPool(LayeredPool* layered_pool) OVERRIDE;
-
   virtual base::DictionaryValue* GetInfoAsValue(
       const std::string& name,
       const std::string& type,
@@ -166,9 +159,6 @@ class NET_EXPORT_PRIVATE SOCKSClientSocketPool
 
   virtual ClientSocketPoolHistograms* histograms() const OVERRIDE;
 
-  // LayeredPool implementation.
-  virtual bool CloseOneIdleConnection() OVERRIDE;
-
  private:
   typedef ClientSocketPoolBase<SOCKSSocketParams> PoolBase;
 
diff --git a/net/socket/ssl_client_socket_pool.cc b/net/socket/ssl_client_socket_pool.cc
index 53a84c0..0c96546 100644
--- a/net/socket/ssl_client_socket_pool.cc
+++ b/net/socket/ssl_client_socket_pool.cc
@@ -479,21 +479,9 @@ SSLClientSocketPool::SSLClientSocketPool(
       ssl_config_service_(ssl_config_service) {
   if (ssl_config_service_)
     ssl_config_service_->AddObserver(this);
-  if (transport_pool_)
-    transport_pool_->AddLayeredPool(this);
-  if (socks_pool_)
-    socks_pool_->AddLayeredPool(this);
-  if (http_proxy_pool_)
-    http_proxy_pool_->AddLayeredPool(this);
 }
 
 SSLClientSocketPool::~SSLClientSocketPool() {
-  if (http_proxy_pool_)
-    http_proxy_pool_->RemoveLayeredPool(this);
-  if (socks_pool_)
-    socks_pool_->RemoveLayeredPool(this);
-  if (transport_pool_)
-    transport_pool_->RemoveLayeredPool(this);
   if (ssl_config_service_)
     ssl_config_service_->RemoveObserver(this);
 }
@@ -546,13 +534,6 @@ void SSLClientSocketPool::Flush() {
   base_.Flush();
 }
 
-bool SSLClientSocketPool::IsStalled() const {
-  return base_.IsStalled() ||
-      (transport_pool_ && transport_pool_->IsStalled()) ||
-      (socks_pool_ && socks_pool_->IsStalled()) ||
-      (http_proxy_pool_ && http_proxy_pool_->IsStalled());
-}
-
 void SSLClientSocketPool::CloseIdleSockets() {
   base_.CloseIdleSockets();
 }
@@ -571,14 +552,6 @@ LoadState SSLClientSocketPool::GetLoadState(
   return base_.GetLoadState(group_name, handle);
 }
 
-void SSLClientSocketPool::AddLayeredPool(LayeredPool* layered_pool) {
-  base_.AddLayeredPool(layered_pool);
-}
-
-void SSLClientSocketPool::RemoveLayeredPool(LayeredPool* layered_pool) {
-  base_.RemoveLayeredPool(layered_pool);
-}
-
 DictionaryValue* SSLClientSocketPool::GetInfoAsValue(
     const std::string& name,
     const std::string& type,
@@ -618,10 +591,4 @@ void SSLClientSocketPool::OnSSLConfigChanged() {
   Flush();
 }
 
-bool SSLClientSocketPool::CloseOneIdleConnection() {
-  if (base_.CloseOneIdleSocket())
-    return true;
-  return base_.CloseOneIdleConnectionInLayeredPool();
-}
-
 }  // namespace net
diff --git a/net/socket/ssl_client_socket_pool.h b/net/socket/ssl_client_socket_pool.h
index 730f0e3..bd667ff 100644
--- a/net/socket/ssl_client_socket_pool.h
+++ b/net/socket/ssl_client_socket_pool.h
@@ -166,7 +166,6 @@ class SSLConnectJob : public ConnectJob {
 
 class NET_EXPORT_PRIVATE SSLClientSocketPool
     : public ClientSocketPool,
-      public LayeredPool,
       public SSLConfigService::Observer {
  public:
   // Only the pools that will be used are required. i.e. if you never
@@ -212,8 +211,6 @@ class NET_EXPORT_PRIVATE SSLClientSocketPool
 
   virtual void Flush() OVERRIDE;
 
-  virtual bool IsStalled() const OVERRIDE;
-
   virtual void CloseIdleSockets() OVERRIDE;
 
   virtual int IdleSocketCount() const OVERRIDE;
@@ -225,10 +222,6 @@ class NET_EXPORT_PRIVATE SSLClientSocketPool
       const std::string& group_name,
       const ClientSocketHandle* handle) const OVERRIDE;
 
-  virtual void AddLayeredPool(LayeredPool* layered_pool) OVERRIDE;
-
-  virtual void RemoveLayeredPool(LayeredPool* layered_pool) OVERRIDE;
-
   virtual base::DictionaryValue* GetInfoAsValue(
       const std::string& name,
       const std::string& type,
@@ -238,9 +231,6 @@ class NET_EXPORT_PRIVATE SSLClientSocketPool
 
   virtual ClientSocketPoolHistograms* histograms() const OVERRIDE;
 
-  // LayeredPool implementation.
-  virtual bool CloseOneIdleConnection() OVERRIDE;
-
  private:
   typedef ClientSocketPoolBase<SSLSocketParams> PoolBase;
 
diff --git a/net/socket/transport_client_socket_pool.cc b/net/socket/transport_client_socket_pool.cc
index a00e810..d11099f 100644
--- a/net/socket/transport_client_socket_pool.cc
+++ b/net/socket/transport_client_socket_pool.cc
@@ -449,10 +449,6 @@ void TransportClientSocketPool::Flush() {
   base_.Flush();
 }
 
-bool TransportClientSocketPool::IsStalled() const {
-  return base_.IsStalled();
-}
-
 void TransportClientSocketPool::CloseIdleSockets() {
   base_.CloseIdleSockets();
 }
@@ -471,14 +467,6 @@ LoadState TransportClientSocketPool::GetLoadState(
   return base_.GetLoadState(group_name, handle);
 }
 
-void TransportClientSocketPool::AddLayeredPool(LayeredPool* layered_pool) {
-  base_.AddLayeredPool(layered_pool);
-}
-
-void TransportClientSocketPool::RemoveLayeredPool(LayeredPool* layered_pool) {
-  base_.RemoveLayeredPool(layered_pool);
-}
-
 DictionaryValue* TransportClientSocketPool::GetInfoAsValue(
     const std::string& name,
     const std::string& type,
diff --git a/net/socket/transport_client_socket_pool.h b/net/socket/transport_client_socket_pool.h
index ef3f6fa..a4b4143 100644
--- a/net/socket/transport_client_socket_pool.h
+++ b/net/socket/transport_client_socket_pool.h
@@ -157,7 +157,6 @@ class NET_EXPORT_PRIVATE TransportClientSocketPool : public ClientSocketPool {
                              StreamSocket* socket,
                              int id) OVERRIDE;
   virtual void Flush() OVERRIDE;
-  virtual bool IsStalled() const OVERRIDE;
   virtual void CloseIdleSockets() OVERRIDE;
   virtual int IdleSocketCount() const OVERRIDE;
   virtual int IdleSocketCountInGroup(
@@ -165,8 +164,6 @@ class NET_EXPORT_PRIVATE TransportClientSocketPool : public ClientSocketPool {
   virtual LoadState GetLoadState(
       const std::string& group_name,
       const ClientSocketHandle* handle) const OVERRIDE;
-  virtual void AddLayeredPool(LayeredPool* layered_pool) OVERRIDE;
-  virtual void RemoveLayeredPool(LayeredPool* layered_pool) OVERRIDE;
   virtual base::DictionaryValue* GetInfoAsValue(
       const std::string& name,
       const std::string& type,