Factoring GUID generation from metrics to base

base/rand_util_win.cc

Index: base/rand_util_win.cc
diff --git a/base/rand_util_win.cc b/base/rand_util_win.cc
index ec0411efd3add4ba6be9d1ab57c53deb9c32cadf..5437177135ff9ba7376817ad21b421f2c30b38fe 100644
--- a/base/rand_util_win.cc
+++ b/base/rand_util_win.cc
@@ -6,8 +6,13 @@
 
 #include <stdlib.h>
 
+#include <objbase.h>
+#include <windows.h>
+
 #include "base/basictypes.h"
 #include "base/logging.h"
+#include "base/string_util.h"
+#include "base/utf_string_conversions.h"
 
 namespace {
 
@@ -27,4 +32,19 @@ uint64 RandUint64() {
   return (static_cast<uint64>(first_half) << 32) + second_half;
 }
 
+std::string GenerateGUID() {
+  const int kGUIDSize = 39;
+
+  GUID guid;
+  HRESULT guid_result = CoCreateGuid(&guid);
+  DCHECK(SUCCEEDED(guid_result));
+
+  std::wstring guid_string;
+  int result = StringFromGUID2(guid,
+                               WriteInto(&guid_string, kGUIDSize), kGUIDSize);
+  DCHECK(result == kGUIDSize);
+
+  return WideToUTF8(guid_string.substr(1, guid_string.length() - 2));
+}
+
 }  // namespace base