Chrome power profiler service

content/browser/power_profiler/power_data_provider_factory.h

+// 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.
+
+#ifndef CONTENT_BROWSER_POWER_PROFILER_POWER_DATA_PROVIDER_FACTORY_H_
+#define CONTENT_BROWSER_POWER_PROFILER_POWER_DATA_PROVIDER_FACTORY_H_
+
+#include "base/memory/scoped_ptr.h"
+#include "content/browser/power_profiler/power_data_provider.h"
+
+namespace content {
+
+class PowerDataProviderFactory {

[jam, 2014/02/24 21:53:46]

what is the point of this factory?

[Pan, 2014/02/25 01:20:39]

to create power data provider for specific platform,
a comment added, thanks.

[jam, 2014/02/25 19:27:25]

you don't need a separate class factory for that. for this platform specific
implementation, a pattern we use is to have a static method, i.e.
PowerDataProvder::Create(). then each different platform's implementation file
(i.e. power_data_provider_win.cc) has that method.

[Pan, 2014/02/26 00:17:05]

thanks, not only OS, but also hardware platform. for example we will have:
power_data_provider_ia derives from power_data_provider, and then
power_data_provider_ia_win, power_data_provider_ia_mac, to impl etc.
so in the static Create, there should be macros like:
#if defined(ARCH_CPU_X86_FAMILY)
  ...new PowerDataProviderIA()...
then the specific OS impls will be handled through gyp.
in this way, I think a factory make things clear, make sense?

[jam, 2014/02/26 17:40:42]

I still don't understand why this makes things clear? you already need gyp rules
to pick the right file. so why not have each platform/os file have the static
method in it. otherwise you have this factory header/implementation file, and it
will need a set of ifdefs in the implementation of the method, and also in the
include section

+ public:
+  // Create a provider, and transfer the ownership to PowerProfilerService.
+  static scoped_ptr<PowerDataProvider> Create();
+
+ private:
+  PowerDataProviderFactory() {}
+  DISALLOW_COPY_AND_ASSIGN(PowerDataProviderFactory);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_POWER_PROFILER_POWER_DATA_PROVIDER_FACTORY_H_