libwebp: update to 0.5.0

third_party/libwebp/enc/backward_references.h

Index: third_party/libwebp/enc/backward_references.h
diff --git a/third_party/libwebp/enc/backward_references.h b/third_party/libwebp/enc/backward_references.h
index c2c81c56e897a218496ba4a6af074cab1a9e7cbc..daa084d84681b54d022ae0d0dd59176683178a8a 100644
--- a/third_party/libwebp/enc/backward_references.h
+++ b/third_party/libwebp/enc/backward_references.h
@@ -22,13 +22,8 @@
 extern "C" {
 #endif
 
-// The spec allows 11, we use 9 bits to reduce memory consumption in encoding.
-// Having 9 instead of 11 only removes about 0.25 % of compression density.
-#define MAX_COLOR_CACHE_BITS 9
-
-// Max ever number of codes we'll use:
-#define PIX_OR_COPY_CODES_MAX \
-    (NUM_LITERAL_CODES + NUM_LENGTH_CODES + (1 << MAX_COLOR_CACHE_BITS))
+// The maximum allowed limit is 11.
+#define MAX_COLOR_CACHE_BITS 10
 
 // -----------------------------------------------------------------------------
 // PixOrCopy
@@ -190,21 +185,16 @@ static WEBP_INLINE void VP8LRefsCursorNext(VP8LRefsCursor* const c) {
 // Main entry points
 
 // Evaluates best possible backward references for specified quality.
-// Further optimize for 2D locality if use_2d_locality flag is set.
+// The input cache_bits to 'VP8LGetBackwardReferences' sets the maximum cache
+// bits to use (passing 0 implies disabling the local color cache).
+// The optimal cache bits is evaluated and set for the *cache_bits parameter.
 // The return value is the pointer to the best of the two backward refs viz,
 // refs[0] or refs[1].
 VP8LBackwardRefs* VP8LGetBackwardReferences(
     int width, int height, const uint32_t* const argb, int quality,
-    int cache_bits, int use_2d_locality, VP8LHashChain* const hash_chain,
+    int low_effort, int* const cache_bits, VP8LHashChain* const hash_chain,
     VP8LBackwardRefs refs[2]);
 
-// Produce an estimate for a good color cache size for the image.
-int VP8LCalculateEstimateForCacheSize(const uint32_t* const argb,
-                                      int xsize, int ysize, int quality,
-                                      VP8LHashChain* const hash_chain,
-                                      VP8LBackwardRefs* const ref,
-                                      int* const best_cache_bits);
-
 #ifdef __cplusplus
 }
 #endif