metrics/base: log whether drives have seek penalties.

chrome/browser/metrics/disk_metrics_provider.cc

+// Copyright 2015 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 "chrome/browser/metrics/disk_metrics_provider.h"
+
+#include "base/bind.h"
+#include "base/files/file_path.h"
+#include "base/location.h"
+#include "base/logging.h"
+#include "base/path_service.h"
+#include "base/sys_info.h"
+#include "chrome/common/chrome_paths.h"
+#include "components/metrics/proto/system_profile.pb.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace {
+
+DiskMetrics GetDiskMetrics() {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::FILE);
+
+  DiskMetrics metrics;
+
+  base::FilePath app_dir;
+  if (PathService::Get(chrome::DIR_APP, &app_dir)) {
+    metrics.app_disk.success = base::SysInfo::HasSeekPenalty(
+        app_dir, &metrics.app_disk.has_seek_penalty);
+  }
+
+  base::FilePath user_data_dir;
+  if (PathService::Get(chrome::DIR_USER_DATA, &user_data_dir)) {
+    metrics.user_data_disk.success = base::SysInfo::HasSeekPenalty(
+        user_data_dir, &metrics.user_data_disk.has_seek_penalty);
+  }
+
+  return metrics;
+}
+
+}  // namespace
+
+DiskMetricsProvider::DiskMetricsProvider() : weak_ptr_factory_(this) {
+  content::BrowserThread::PostTaskAndReplyWithResult(
+      content::BrowserThread::FILE, FROM_HERE,

[Alexei Svitkine (slow), 2015/03/12 16:41:06]

Any reason to use FILE thread explicitly rather than blocking pool?

Note: If you move this to the component, you can pass the task runner to the
ctor.

[Dan Beam, 2015/03/13 19:31:32]

can't be in components/ AFAIU because it depends on chrome/*
(common/chrome_paths.h)

+      base::Bind(&GetDiskMetrics),
+      base::Bind(&DiskMetricsProvider::GotDiskMetrics,
+                 weak_ptr_factory_.GetWeakPtr()));
+}
+
+DiskMetricsProvider::~DiskMetricsProvider() {}
+
+void DiskMetricsProvider::ProvideSystemProfileMetrics(
+    metrics::SystemProfileProto* system_profile_proto) {
+  if (metrics_.app_disk.success) {

[Alexei Svitkine (slow), 2015/03/12 16:41:06]

Nit: You can make a helper that takes metrics_.app_disk and 
system_profile_proto->mutable_hardware()->mutable_app_disk() and then just call
it twice for the two disks.

[Dan Beam, 2015/03/13 19:31:32]

Done.

+    system_profile_proto->mutable_hardware()->mutable_app_disk()->
+        set_has_seek_penalty(metrics_.app_disk.has_seek_penalty);
+  }
+  if (metrics_.user_data_disk.success) {
+    system_profile_proto->mutable_hardware()->mutable_user_data_disk()->
+        set_has_seek_penalty(metrics_.user_data_disk.has_seek_penalty);
+  }
+}
+
+SeekPenaltyResponse::SeekPenaltyResponse() : success(false) {}
+
+void DiskMetricsProvider::GotDiskMetrics(const DiskMetrics& metrics) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  metrics_ = metrics;
+}