Use the upstream version of libwebp, v0.4.3.

third_party/libwebp/utils/color_cache.c

Index: third_party/libwebp/utils/color_cache.c
diff --git a/third_party/libwebp/utils/color_cache.c b/third_party/libwebp/utils/color_cache.c
new file mode 100644
index 0000000000000000000000000000000000000000..8a88f08b70ce5506368894fd771b4371f47c050b
--- /dev/null
+++ b/third_party/libwebp/utils/color_cache.c
@@ -0,0 +1,39 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Color Cache for WebP Lossless
+//
+// Author: Jyrki Alakuijala (jyrki@google.com)
+
+#include <assert.h>
+#include <stdlib.h>
+#include "./color_cache.h"
+#include "../utils/utils.h"
+
+//------------------------------------------------------------------------------
+// VP8LColorCache.
+
+int VP8LColorCacheInit(VP8LColorCache* const cc, int hash_bits) {
+  const int hash_size = 1 << hash_bits;
+  assert(cc != NULL);
+  assert(hash_bits > 0);
+  cc->colors_ = (uint32_t*)WebPSafeCalloc((uint64_t)hash_size,
+                                          sizeof(*cc->colors_));
+  if (cc->colors_ == NULL) return 0;
+  cc->hash_shift_ = 32 - hash_bits;
+  return 1;
+}
+
+void VP8LColorCacheClear(VP8LColorCache* const cc) {
+  if (cc != NULL) {
+    WebPSafeFree(cc->colors_);
+    cc->colors_ = NULL;
+  }
+}
+