Do not leak memory in base::OS::FOpen.

R=petermarshall@chromium.org

Change-Id: Ie62129f39e1085a94737406dc07b07e359294c4e
Reviewed-on: https://chromium-review.googlesource.com/599813Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47152}

src/base/platform/platform-posix.cc

@@ -400,7 +400,10 @@ FILE* OS::FOpen(const char* path, const char* mode) {
   FILE* file = fopen(path, mode);
   if (file == NULL) return NULL;
   struct stat file_stat;
-  if (fstat(fileno(file), &file_stat) != 0) return NULL;
+  if (fstat(fileno(file), &file_stat) != 0) {
+    fclose(file);
+    return NULL;
+  }
   bool is_regular_file = ((file_stat.st_mode & S_IFREG) != 0);
   if (is_regular_file) return file;
   fclose(file);