Change NOTREACHED for a LOG(WARNING) when we can't delete

the cache. This should help the unit tests.

BUG:38562
Review URL: http://codereview.chromium.org/1594002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@43446 0039d316-1c4b-4281-b951-d872f2087c98

net/disk_cache/cache_util_posix.cc

@@ -20,13 +20,17 @@ void DeleteCache(const FilePath& path, bool remove_folder) {
                                  /* recursive */ false,
                                  file_util::FileEnumerator::FILES);
   for (FilePath file = iter.Next(); !file.value().empty(); file = iter.Next()) {
-    if (!file_util::Delete(file, /* recursive */ false))
-      NOTREACHED();
+    if (!file_util::Delete(file, /* recursive */ false)) {
+      LOG(WARNING) << "Unable to delete cache.";
+      return;
+    }
   }
 
   if (remove_folder) {
-    if (!file_util::Delete(path, /* recursive */ false))
-      NOTREACHED();
+    if (!file_util::Delete(path, /* recursive */ false)) {
+      LOG(WARNING) << "Unable to delete cache folder.";
+      return;
+    }
   }
 }