Make sure that net_perftest doesn't leave temporary files.

net/disk_cache/disk_cache_test_util.cc

Index: net/disk_cache/disk_cache_test_util.cc
diff --git a/net/disk_cache/disk_cache_test_util.cc b/net/disk_cache/disk_cache_test_util.cc
index 9a15209eb4cf7acf618dadc09c8d8021ad276a8d..555b2e58eaa91b9af70b8bf70a08aa95ecee54ac 100644
--- a/net/disk_cache/disk_cache_test_util.cc
+++ b/net/disk_cache/disk_cache_test_util.cc
@@ -4,6 +4,7 @@
 
 #include "net/disk_cache/disk_cache_test_util.h"
 
+#include "base/logging.h"
 #include "base/file_util.h"
 #include "base/path_service.h"
 #include "net/disk_cache/backend_impl.h"
@@ -77,6 +78,15 @@ bool CheckCacheIntegrity(const std::wstring& path) {
   return cache->SelfCheck() >= 0;
 }
 
+ScopedTestCache::ScopedTestCache() : path_(GetCachePath()) {
+  bool result = DeleteCache(path_.c_str());
+  DCHECK(result);
+}
+
+ScopedTestCache::~ScopedTestCache() {
+  file_util::Delete(path(), true);
+}
+
 // -----------------------------------------------------------------------
 
 int g_cache_tests_max_id = 0;