Revert of Temporary: Detect WebSocket destruction order problem (patchset #2...

Revert of Temporary: Detect WebSocket destruction order problem (patchset #2 id:20001 of https://codereview.chromium.org/2315213002/ )

Reason for revert:
We have learnt everything we are going to learn
from this CHECK. Reverting as intended.

This does not need to be relanded.

Original issue's description:
> Temporary: Detect WebSocket destruction order problem
>
> Add a CHECK() to crash the browser if a destruction order problem is
> encountered.
>
> This will be reverted once the information is collected.
>
> BUG=641013
>
> Committed: https://crrev.com/23169a0f5421e6759d89b1feaa83b06b197a7039
> Cr-Commit-Position: refs/heads/master@{#417522}

TBR=yhirano@chromium.org,mmenke@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=641013

Review-Url: https://codereview.chromium.org/2340253002
Cr-Commit-Position: refs/heads/master@{#418791}

net/http/http_network_session.cc

@@ -241,9 +241,6 @@ HttpNetworkSession::HttpNetworkSession(const Params& params)
 HttpNetworkSession::~HttpNetworkSession() {
   base::STLDeleteElements(&response_drainers_);
   spdy_session_pool_.CloseAllSessions();
-
-  // TODO(ricea): Remove this by October 2016. See bug 641013.
-  CHECK_EQ(active_websockets_, 0);
 }
 
 void HttpNetworkSession::AddResponseDrainer(HttpResponseBodyDrainer* drainer) {

net/http/http_network_session.h

@@ -273,10 +273,6 @@ class NET_EXPORT HttpNetworkSession
                     SSLConfig* server_config,
                     SSLConfig* proxy_config) const;
 
-  // TODO(ricea): Remove this by October 2016.
-  void IncrementActiveWebSockets() { ++active_websockets_; }
-  void DecrementActiveWebSockets() { --active_websockets_; }
-
  private:
   friend class HttpNetworkSessionPeer;
 
@@ -311,9 +307,6 @@ class NET_EXPORT HttpNetworkSession
   Params params_;
 
   std::unique_ptr<base::MemoryPressureListener> memory_pressure_listener_;
-
-  // TODO(ricea): Remove this by October 2016.
-  int active_websockets_ = 0;
 };
 
 }  // namespace net

net/websockets/websocket_channel.cc

@@ -25,13 +25,10 @@
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
 #include "net/base/io_buffer.h"
-#include "net/http/http_network_session.h"  // TODO(ricea): Remove
 #include "net/http/http_request_headers.h"
 #include "net/http/http_response_headers.h"
-#include "net/http/http_transaction_factory.h"  // TODO(ricea): Remove
 #include "net/http/http_util.h"
 #include "net/log/net_log.h"
-#include "net/url_request/url_request_context.h"  // TODO(ricea): Remove
 #include "net/websockets/websocket_errors.h"
 #include "net/websockets/websocket_event_interface.h"
 #include "net/websockets/websocket_frame.h"
@@ -330,14 +327,6 @@ WebSocketChannel::WebSocketChannel(
       initial_frame_forwarded_(false) {}
 
 WebSocketChannel::~WebSocketChannel() {
-  // TODO(ricea): Remove this by October 2016. See bug 641013.
-  if (stream_) {
-    HttpTransactionFactory* http_transaction_factory =
-        url_request_context_->http_transaction_factory();
-    if (http_transaction_factory)
-      http_transaction_factory->GetSession()->DecrementActiveWebSockets();
-  }
-
   // The stream may hold a pointer to read_frames_, and so it needs to be
   // destroyed first.
   stream_.reset();
@@ -609,12 +598,6 @@ void WebSocketChannel::OnConnectSuccess(
 
   stream_ = std::move(stream);
 
-  // TODO(ricea): Remove this before October 2016.
-  HttpTransactionFactory* http_transaction_factory =
-      url_request_context_->http_transaction_factory();
-  if (http_transaction_factory)
-    http_transaction_factory->GetSession()->IncrementActiveWebSockets();
-
   SetState(CONNECTED);
 
   if (event_interface_->OnAddChannelResponse(stream_->GetSubProtocol(),