QUIC - Browser shutdown crash fix. Accessing disk_cache's backend after

net/http/disk_cache_based_quic_server_info.cc

 // Copyright 2014 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/http/disk_cache_based_quic_server_info.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/callback_helpers.h"
 #include "base/logging.h"
@@ skipping 86 matching lines @@
     }
     wait_for_ready_callback_ = callback;
   }
 
   return ERR_IO_PENDING;
 }
 
 void DiskCacheBasedQuicServerInfo::CancelWaitForDataReadyCallback() {
   DCHECK(CalledOnValidThread());
 
-  RecordQuicServerInfoStatus(QUIC_SERVER_INFO_WAIT_FOR_DATA_READY_CANCEL);
+  // TODO(rtenneti): crbug.com/456524. Implement a better fix. During shutdown,
+  // HttpCache could be deleted and leads to crash because backend_ is deleted.
+  // Temporary weekend fix is to return without collecting data in histograms.
+  // RecordQuicServerInfoStatus(QUIC_SERVER_INFO_WAIT_FOR_DATA_READY_CANCEL);
   if (!wait_for_ready_callback_.is_null()) {
     RecordLastFailure();
     wait_for_ready_callback_.Reset();
   }
 }
 
 bool DiskCacheBasedQuicServerInfo::IsDataReady() {
   return ready_;
 }
 
@@ skipping 371 matching lines @@
   } else if (backend_->GetCacheType() == net::MEMORY_CACHE) {
     UMA_HISTOGRAM_ENUMERATION("Net.QuicDiskCache.FailureReason.MemoryCache",
                               failure, NUM_OF_FAILURES);
   } else {
     UMA_HISTOGRAM_ENUMERATION("Net.QuicDiskCache.FailureReason.DiskCache",
                               failure, NUM_OF_FAILURES);
   }
 }
 
 }  // namespace net