UMA stats for MTP file system in Chrome OS Files.app.

chrome/browser/chromeos/file_manager/volume_manager.cc

 // Copyright 2013 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/chromeos/file_manager/volume_manager.h"
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/memory/singleton.h"
+#include "base/metrics/histogram.h"
 #include "base/prefs/pref_service.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/chromeos/drive/drive_integration_service.h"
 #include "chrome/browser/chromeos/drive/file_errors.h"
 #include "chrome/browser/chromeos/drive/file_system_interface.h"
 #include "chrome/browser/chromeos/drive/file_system_util.h"
 #include "chrome/browser/chromeos/file_manager/mounted_disk_monitor.h"
 #include "chrome/browser/chromeos/file_manager/path_util.h"
 #include "chrome/browser/chromeos/file_manager/volume_manager_factory.h"
 #include "chrome/browser/chromeos/file_manager/volume_manager_observer.h"
@@ skipping 697 matching lines @@
       fileapi::ExternalMountPoints::GetSystemInstance()->RegisterFileSystem(
           fsid, fileapi::kFileSystemTypeDeviceMediaAsFileStorage,
           fileapi::FileSystemMountOption(), path);
   DCHECK(result);
   content::BrowserThread::PostTask(
       content::BrowserThread::IO, FROM_HERE, base::Bind(
           &MTPDeviceMapService::RegisterMTPFileSystem,
           base::Unretained(MTPDeviceMapService::GetInstance()),
           info.location(), fsid));
 
+  UMA_HISTOGRAM_COUNTS("FileBrowser.MTPMount", 1);

[Ilya Sherman, 2014/05/01 21:15:24]

You're currently allocating space for 50 buckets, and only using one of them. 
Please only allocate as many buckets as you need.

[kinaba, 2014/05/08 04:15:41]

Done.

+
   VolumeInfo volume_info;
   volume_info.type = VOLUME_TYPE_MTP;
   volume_info.mount_path = path;
   volume_info.mount_condition = chromeos::disks::MOUNT_CONDITION_NONE;
   volume_info.is_parent = true;
   volume_info.is_read_only = true;
   volume_info.volume_id = "mtp:" + name;
   volume_info.source_path = path;
   volume_info.device_type = chromeos::DEVICE_TYPE_MOBILE;
   DoMountEvent(chromeos::MOUNT_ERROR_NONE, volume_info, false);
@@ skipping 72 matching lines @@
     return;
   if (error_code == chromeos::MOUNT_ERROR_NONE)
     mounted_volumes_.erase(volume_info.volume_id);
 
   FOR_EACH_OBSERVER(VolumeManagerObserver,
                     observers_,
                     OnVolumeUnmounted(error_code, volume_info));
 }
 
 }  // namespace file_manager