Initialize StatisticsRecorder in Child Process to hold

content/common/child_process.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 "content/common/child_process.h"
 
 #if defined(OS_POSIX) && !defined(OS_ANDROID)
 #include <signal.h>  // For SigUSR1Handler below.
 #endif
 
 #include "base/message_loop.h"
+#include "base/metrics/statistics_recorder.h"
 #include "base/process_util.h"
 #include "base/string_number_conversions.h"
 #include "base/threading/thread.h"
 #include "base/utf_string_conversions.h"
 #include "content/common/child_thread.h"
 
 #if defined(OS_ANDROID)
 #include "base/debug/debugger.h"
 #endif
 
 #if defined(OS_POSIX) && !defined(OS_ANDROID)
 static void SigUSR1Handler(int signal) { }
 #endif
 
 ChildProcess* ChildProcess::child_process_;
 
 ChildProcess::ChildProcess()
     : ref_count_(0),
       shutdown_event_(true, false),
       io_thread_("Chrome_ChildIOThread") {
   DCHECK(!child_process_);
   child_process_ = this;
 
+  // Initialize histogram statistics gathering system.
+  // Don't create StatisticsRecorder in the single process mode.
+  if (!base::StatisticsRecorder::IsActive()) {
+    statistics_recorder_.reset(new base::StatisticsRecorder());
+  }
+
   // We can't recover from failing to start the IO thread.
   CHECK(io_thread_.StartWithOptions(
             base::Thread::Options(MessageLoop::TYPE_IO, 0)));
 }
 
 ChildProcess::~ChildProcess() {
   DCHECK(child_process_ == this);
 
   // Signal this event before destroying the child process.  That way all
   // background threads can cleanup.
   // For example, in the renderer the RenderThread instances will be able to
   // notice shutdown before the render process begins waiting for them to exit.
   shutdown_event_.Signal();
 
   // Kill the main thread object before nulling child_process_, since
   // destruction code might depend on it.
   main_thread_.reset();
 
+  statistics_recorder_.reset();

[jam, 2012/07/18 01:22:06]

nit: is this necessary? if not, leave it out

[ramant (doing other things), 2012/07/18 03:20:32]

Done.

+
   child_process_ = NULL;
 }
 
 ChildThread* ChildProcess::main_thread() {
   return main_thread_.get();
 }
 
 void ChildProcess::set_main_thread(ChildThread* thread) {
   main_thread_.reset(thread);
 }
@@ skipping 51 matching lines @@
   // Install a signal handler so that pause can be woken.
   struct sigaction sa;
   memset(&sa, 0, sizeof(sa));
   sa.sa_handler = SigUSR1Handler;
   sigaction(SIGUSR1, &sa, NULL);
 
   pause();
 #endif  // defined(OS_ANDROID)
 #endif  // defined(OS_POSIX)
 }