[HttpCache] Store some memcache info to memory dumps for debugging

net/disk_cache/blockfile/backend_impl.cc

 // Copyright (c) 2012 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/disk_cache/blockfile/backend_impl.h"
 
 #include <limits>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/files/file.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/hash.h"
 #include "base/location.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "base/rand_util.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/sys_info.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
+#include "base/trace_event/process_memory_dump.h"
 #include "net/base/net_errors.h"
 #include "net/disk_cache/blockfile/disk_format.h"
 #include "net/disk_cache/blockfile/entry_impl.h"
 #include "net/disk_cache/blockfile/errors.h"
 #include "net/disk_cache/blockfile/experiments.h"
 #include "net/disk_cache/blockfile/file.h"
 #include "net/disk_cache/blockfile/histogram_macros.h"
 #include "net/disk_cache/blockfile/webfonts_histogram.h"
 #include "net/disk_cache/cache_util.h"
 
@@ skipping 1274 matching lines @@
   item.second = "Blockfile Cache";
   stats->push_back(item);
 
   stats_.GetItems(stats);
 }
 
 void BackendImpl::OnExternalCacheHit(const std::string& key) {
   background_queue_.OnExternalCacheHit(key);
 }
 
-size_t BackendImpl::EstimateMemoryUsage() const {
+size_t BackendImpl::DumpMemoryStats(
+    base::trace_event::ProcessMemoryDump* pmd,
+    const std::string& parent_absolute_name) const {
   // TODO(xunjieli): Implement this. crbug.com/669108.
-  return 0;
+  return 0u;
 }
 
 // ------------------------------------------------------------------------
 
 // We just created a new file so we're going to write the header and set the
 // file length to include the hash table (zero filled).
 bool BackendImpl::CreateBackingStore(disk_cache::File* file) {
   AdjustMaxCacheSize(0);
 
   IndexHeader header;
@@ skipping 755 matching lines @@
     if (total_memory > kMaxBuffersSize || total_memory <= 0)
       total_memory = kMaxBuffersSize;
 
     done = true;
   }
 
   return static_cast<int>(total_memory);
 }
 
 }  // namespace disk_cache