Update from https://crrev.com/316786

net/websockets/websocket_stream.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/websockets/websocket_stream.h"
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/sparse_histogram.h"
 #include "base/profiler/scoped_tracker.h"
+#include "base/strings/stringprintf.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
 #include "net/base/load_flags.h"
 #include "net/http/http_request_headers.h"
 #include "net/http/http_response_headers.h"
 #include "net/http/http_status_code.h"
 #include "net/url_request/redirect_info.h"
 #include "net/url_request/url_request.h"
 #include "net/url_request/url_request_context.h"
 #include "net/websockets/websocket_errors.h"
@@ skipping 106 matching lines @@
                              base::Unretained(this)));
     url_request_->Start();
   }
 
   void PerformUpgrade() {
     DCHECK(timer_);
     timer_->Stop();
     connect_delegate_->OnSuccess(create_helper_->Upgrade());
   }
 
+  std::string FailureMessageFromNetError() {
+    int error = url_request_->status().error();
+    if (error == ERR_TUNNEL_CONNECTION_FAILED) {
+      // This error is common and confusing, so special-case it.
+      // TODO(ricea): Include the HostPortPair of the selected proxy server in
+      // the error message. This is not currently possible because it isn't set
+      // in HttpResponseInfo when a ERR_TUNNEL_CONNECTION_FAILED error happens.
+      return "Establishing a tunnel via proxy server failed.";
+    } else {
+      return std::string("Error in connection establishment: ") +
+             ErrorToString(url_request_->status().error());
+    }
+  }
+
   void ReportFailure() {
     DCHECK(timer_);
     timer_->Stop();
     if (failure_message_.empty()) {
       switch (url_request_->status().status()) {
         case URLRequestStatus::SUCCESS:
         case URLRequestStatus::IO_PENDING:
           break;
         case URLRequestStatus::CANCELED:
           if (url_request_->status().error() == ERR_TIMED_OUT)
             failure_message_ = "WebSocket opening handshake timed out";
           else
             failure_message_ = "WebSocket opening handshake was canceled";
           break;
         case URLRequestStatus::FAILED:
-          failure_message_ =
-              std::string("Error in connection establishment: ") +
-              ErrorToString(url_request_->status().error());
+          failure_message_ = FailureMessageFromNetError();
           break;
       }
     }
     ReportFailureWithMessage(failure_message_);
   }
 
   void ReportFailureWithMessage(const std::string& failure_message) {
     connect_delegate_->OnFailure(failure_message);
   }
 
@@ skipping 184 matching lines @@
     connect_delegate->OnFinishOpeningHandshake(make_scoped_ptr(
         new WebSocketHandshakeResponseInfo(url,
                                            headers->response_code(),
                                            headers->GetStatusText(),
                                            headers,
                                            response_time)));
   }
 }
 
 }  // namespace net