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

net/http/http_cache.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/http/http_cache.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 112 matching lines @@
 //-----------------------------------------------------------------------------
 
 // This structure keeps track of work items that are attempting to create or
 // open cache entries or the backend itself.
 struct HttpCache::PendingOp {
   PendingOp() : disk_entry(NULL) {}
   ~PendingOp() {}
 
   // Returns the estimate of dynamically allocated memory in bytes.
   size_t EstimateMemoryUsage() const {
-    // |disk_entry| is tracked in |backend|.
-    return base::trace_event::EstimateMemoryUsage(backend) +
-           base::trace_event::EstimateMemoryUsage(writer) +
+    // Note that backend isn't counted because it doesn't provide an EMU
+    // function.
+    return base::trace_event::EstimateMemoryUsage(writer) +
            base::trace_event::EstimateMemoryUsage(pending_queue);
   }
 
   disk_cache::Entry* disk_entry;
   std::unique_ptr<disk_cache::Backend> backend;
   std::unique_ptr<WorkItem> writer;
   CompletionCallback callback;  // BackendCallback.
   WorkItemList pending_queue;
 };
 
@@ skipping 359 matching lines @@
   std::unique_ptr<HttpTransactionFactory> old_network_layer(
       std::move(network_layer_));
   network_layer_ = std::move(new_network_layer);
   return old_network_layer;
 }
 
 void HttpCache::DumpMemoryStats(base::trace_event::ProcessMemoryDump* pmd,
                                 const std::string& parent_absolute_name) const {
   // Skip tracking members like |clock_| and |backend_factory_| because they
   // don't allocate.
-  base::trace_event::MemoryAllocatorDump* dump =
-      pmd->CreateAllocatorDump(parent_absolute_name + "/http_cache");
-  dump->AddScalar(
-      base::trace_event::MemoryAllocatorDump::kNameSize,
-      base::trace_event::MemoryAllocatorDump::kUnitsBytes,
-      base::trace_event::EstimateMemoryUsage(disk_cache_) +
-          base::trace_event::EstimateMemoryUsage(active_entries_) +
-          base::trace_event::EstimateMemoryUsage(doomed_entries_) +
-          base::trace_event::EstimateMemoryUsage(playback_cache_map_) +
-          base::trace_event::EstimateMemoryUsage(pending_ops_));
+  std::string name = parent_absolute_name + "/http_cache";
+  base::trace_event::MemoryAllocatorDump* dump = pmd->CreateAllocatorDump(name);
+  size_t size = base::trace_event::EstimateMemoryUsage(active_entries_) +
+                base::trace_event::EstimateMemoryUsage(doomed_entries_) +
+                base::trace_event::EstimateMemoryUsage(playback_cache_map_) +
+                base::trace_event::EstimateMemoryUsage(pending_ops_);
+  if (disk_cache_)
+    size += disk_cache_->DumpMemoryStats(pmd, name);
+
+  dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
+                  base::trace_event::MemoryAllocatorDump::kUnitsBytes, size);
 }
 
 //-----------------------------------------------------------------------------
 
 int HttpCache::CreateBackend(disk_cache::Backend** backend,
                              const CompletionCallback& callback) {
   if (!backend_factory_.get())
     return ERR_FAILED;
 
   building_backend_ = true;
@@ skipping 660 matching lines @@
     building_backend_ = false;
     DeletePendingOp(pending_op);
   }
 
   // The cache may be gone when we return from the callback.
   if (!item->DoCallback(result, disk_cache_.get()))
     item->NotifyTransaction(result, NULL);
 }
 
 }  // namespace net