Update from https://crrev.com/318214

third_party/brotli/dec/bit_reader.c

Index: third_party/brotli/dec/bit_reader.c
diff --git a/third_party/brotli/dec/bit_reader.c b/third_party/brotli/dec/bit_reader.c
new file mode 100644
index 0000000000000000000000000000000000000000..981dccf5e6723db8d541c01f983c767f07a2a4d7
--- /dev/null
+++ b/third_party/brotli/dec/bit_reader.c
@@ -0,0 +1,50 @@
+/* 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.
+
+   Bit reading helpers
+*/
+
+#include <assert.h>
+#include <stdlib.h>
+
+#include "./bit_reader.h"
+
+#if defined(__cplusplus) || defined(c_plusplus)
+extern "C" {
+#endif
+
+int BrotliInitBitReader(BrotliBitReader* const br, BrotliInput input) {
+  size_t i;
+  assert(br != NULL);
+
+  br->buf_ptr_ = br->buf_;
+  br->input_ = input;
+  br->val_ = 0;
+  br->pos_ = 0;
+  br->bit_pos_ = 0;
+  br->bit_end_pos_ = 0;
+  br->eos_ = 0;
+  if (!BrotliReadMoreInput(br)) {
+    return 0;
+  }
+  for (i = 0; i < sizeof(br->val_); ++i) {
+    br->val_ |= ((uint64_t)br->buf_[br->pos_]) << (8 * i);
+    ++br->pos_;
+  }
+  return (br->bit_end_pos_ > 0);
+}
+
+#if defined(__cplusplus) || defined(c_plusplus)
+}    /* extern "C" */
+#endif