Update from https://crrev.com/318214

third_party/brotli/dec/safe_malloc.c

Index: third_party/brotli/dec/safe_malloc.c
diff --git a/third_party/brotli/dec/safe_malloc.c b/third_party/brotli/dec/safe_malloc.c
new file mode 100644
index 0000000000000000000000000000000000000000..ef1624c72223b6b96f6b52c3547664623cf391e4
--- /dev/null
+++ b/third_party/brotli/dec/safe_malloc.c
@@ -0,0 +1,42 @@
+/* Copyright 2013 Google Inc. All Rights Reserved.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+   http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+
+   Size-checked memory allocation.
+*/
+
+#include <stdlib.h>
+#include "./safe_malloc.h"
+
+#if defined(__cplusplus) || defined(c_plusplus)
+extern "C" {
+#endif
+
+/* Returns 0 in case of overflow of nmemb * size. */
+static int CheckSizeArgumentsOverflow(uint64_t nmemb, size_t size) {
+  const uint64_t total_size = nmemb * size;
+  if (nmemb == 0) return 1;
+  if ((uint64_t)size > BROTLI_MAX_ALLOCABLE_MEMORY / nmemb) return 0;
+  if (total_size != (size_t)total_size) return 0;
+  return 1;
+}
+
+void* BrotliSafeMalloc(uint64_t nmemb, size_t size) {
+  if (!CheckSizeArgumentsOverflow(nmemb, size)) return NULL;
+  assert(nmemb * size > 0);
+  return malloc((size_t)(nmemb * size));
+}
+
+#if defined(__cplusplus) || defined(c_plusplus)
+}    /* extern "C" */
+#endif