[NOT FOR REVIEW] Instrument net/ with trace events.

net/disk_cache/blockfile/in_flight_backend_io.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/in_flight_backend_io.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/single_thread_task_runner.h"
+#include "base/trace_event/trace_event.h"
 #include "net/base/net_errors.h"
 #include "net/disk_cache/blockfile/backend_impl.h"
 #include "net/disk_cache/blockfile/entry_impl.h"
 #include "net/disk_cache/blockfile/histogram_macros.h"
 
 // Provide a BackendImpl object to macros from histogram_macros.h.
 #define CACHE_UMA_BACKEND_IMPL_OBJ backend_
 
 namespace disk_cache {
 
@@ skipping 203 matching lines @@
   return operation_ == OP_OPEN || operation_ == OP_CREATE ||
       operation_ == OP_OPEN_NEXT;
 }
 
 base::TimeDelta BackendIO::ElapsedTime() const {
   return base::TimeTicks::Now() - start_time_;
 }
 
 // Runs on the background thread.
 void BackendIO::ExecuteBackendOperation() {
+  TRACE_EVENT0("net", "net::BackendIO::ExecuteBackendOperation");
   switch (operation_) {
     case OP_INIT:
       result_ = backend_->SyncInit();
       break;
     case OP_OPEN:
       result_ = backend_->SyncOpenEntry(key_, entry_ptr_);
       break;
     case OP_CREATE:
       result_ = backend_->SyncCreateEntry(key_, entry_ptr_);
       break;
@@ skipping 288 matching lines @@
   background_thread_->PostTask(
       FROM_HERE, base::Bind(&BackendIO::ExecuteOperation, operation));
   OnOperationPosted(operation);
 }
 
 base::WeakPtr<InFlightBackendIO> InFlightBackendIO::GetWeakPtr() {
   return ptr_factory_.GetWeakPtr();
 }
 
 }  // namespace