metrics/base: log whether drives have seek penalties.

base/sys_info.h

 // 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.
 
 #ifndef BASE_SYS_INFO_H_
 #define BASE_SYS_INFO_H_
 
 #include <map>
 #include <string>
 
@@ skipping 30 matching lines @@
   // Return the number of megabytes of available virtual memory, or zero if it
   // is unlimited.
   static int AmountOfVirtualMemoryMB() {
     return static_cast<int>(AmountOfVirtualMemory() / 1024 / 1024);
   }
 
   // Return the available disk space in bytes on the volume containing |path|,
   // or -1 on failure.
   static int64 AmountOfFreeDiskSpace(const FilePath& path);
 
+  // Determine whether the device that services |path| has a seek penalty.
+  // Returns false if it couldn't be determined (e.g., |path| doesn't exist) or
+  // |has_seek_penalty| is NULL.

[rvargas (doing something else), 2015/03/12 22:01:11]

The second condition sounds like a DCHECK to me.

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

Done.

+  static bool HasSeekPenalty(const FilePath& path, bool* has_seek_penalty);
+
   // Returns system uptime in milliseconds.
   static int64 Uptime();
 
   // Returns a descriptive string for the current machine model or an empty
   // string if machime model is unknown or an error occured.
   // e.g. MacPro1,1 on Mac.
   // Only implemented on OS X, will return an empty string on other platforms.
   static std::string HardwareModelName();
 
   // Returns the name of the host operating system.
@@ skipping 77 matching lines @@
 
   // Returns true if this is a low-end device.
   // Low-end device refers to devices having less than 512M memory in the
   // current implementation.
   static bool IsLowEndDevice();
 };
 
 }  // namespace base
 
 #endif  // BASE_SYS_INFO_H_