Change the API of disk_cache::CreateCacheBackend to use scoped_ptr

chrome/browser/nacl_host/pnacl_translation_cache.cc

Index: chrome/browser/nacl_host/pnacl_translation_cache.cc
diff --git a/chrome/browser/nacl_host/pnacl_translation_cache.cc b/chrome/browser/nacl_host/pnacl_translation_cache.cc
index 6492e36d7411ed807c6039167151f2847ea8329b..87bb4267c4f7763df0f080c97a75251981908a64 100644
--- a/chrome/browser/nacl_host/pnacl_translation_cache.cc
+++ b/chrome/browser/nacl_host/pnacl_translation_cache.cc
@@ -283,10 +283,9 @@ void PnaclTranslationCache::OpComplete(PnaclTranslationCacheEntry* entry) {
 
 //////////////////////////////////////////////////////////////////////
 // Construction and cache backend initialization
-PnaclTranslationCache::PnaclTranslationCache()
-    : disk_cache_(NULL), in_memory_(false) {}
+PnaclTranslationCache::PnaclTranslationCache() : in_memory_(false) {}
 
-PnaclTranslationCache::~PnaclTranslationCache() { delete disk_cache_; }
+PnaclTranslationCache::~PnaclTranslationCache() {}
 
 int PnaclTranslationCache::InitWithDiskBackend(
     const base::FilePath& cache_dir,