Fix OperationSystemVersion() on Android.

base/sys_info_android.cc

Index: base/sys_info_android.cc
===================================================================
--- base/sys_info_android.cc	(revision 197971)
+++ base/sys_info_android.cc	(working copy)
@@ -7,6 +7,7 @@
 #include <sys/system_properties.h>
 
 #include "base/logging.h"
+#include "base/stringprintf.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_piece.h"
 
@@ -134,6 +135,12 @@
   return std::string(device_model_str);
 }
 
+std::string SysInfo::OperatingSystemVersion() {
+  int32 major, minor, bugfix;
+  OperatingSystemVersionNumbers(&major, &minor, &bugfix);
+  return StringPrintf("%d.%d.%d", major, minor, bugfix);
+}
+
 void SysInfo::OperatingSystemVersionNumbers(int32* major_version,
                                             int32* minor_version,
                                             int32* bugfix_version) {