SessionStorage: Using DeleteDB to delete database.

base::DeleteFile ignores database locks, leveldb_chrome::DeleteDB does
not and is safer.

Bug: 802298
Change-Id: I6b30fb6826216c9e54a16569a133e1fbddfad98f
Reviewed-on: https://chromium-review.googlesource.com/1151543
Commit-Queue: Chris Mumford <cmumford@chromium.org>
Commit-Queue: Daniel Murphy <dmurph@chromium.org>
Reviewed-by: Daniel Murphy <dmurph@chromium.org>
Cr-Commit-Position: refs/heads/master@{#578406}

content/browser/dom_storage/session_storage_database.cc

@@ -7,6 +7,7 @@
 #include <inttypes.h>
 #include <stddef.h>
 
+#include <utility>
 #include <vector>
 
 #include "base/files/file_util.h"
@@ -430,7 +431,11 @@ bool SessionStorageDatabase::LazyOpen(bool create_if_needed) {
                  << ", error: " << s.ToString();
 
     // Clear the directory and try again.
-    base::DeleteFile(file_path_, true);
+    s = leveldb_chrome::DeleteDB(file_path_, leveldb_env::Options());
+    if (!s.ok()) {
+      LOG(WARNING) << "Failed to delete leveldb in " << file_path_.value()
+                   << ", error: " << s.ToString();
+    }
     s = TryToOpen(&db_);
     if (!s.ok()) {
       LOG(WARNING) << "Failed to open leveldb in " << file_path_.value()