libwebp: update to 0.5.0

third_party/libwebp/enc/histogram.h

Index: third_party/libwebp/enc/histogram.h
diff --git a/third_party/libwebp/enc/histogram.h b/third_party/libwebp/enc/histogram.h
index 1cf4c54749fc17ffb867938457b4508a5f766e66..d303d1d58ba61caae7b7e85bc1f08a96340e0ed9 100644
--- a/third_party/libwebp/enc/histogram.h
+++ b/third_party/libwebp/enc/histogram.h
@@ -14,10 +14,6 @@
 #ifndef WEBP_ENC_HISTOGRAM_H_
 #define WEBP_ENC_HISTOGRAM_H_
 
-#include <assert.h>
-#include <stddef.h>
-#include <stdlib.h>
-#include <stdio.h>
 #include <string.h>
 
 #include "./backward_references.h"
@@ -28,6 +24,9 @@
 extern "C" {
 #endif
 
+// Not a trivial literal symbol.
+#define VP8L_NON_TRIVIAL_SYM (0xffffffff)
+
 // A simple container for histograms of data.
 typedef struct {
   // literal_ contains green literal, palette-code and
@@ -39,9 +38,11 @@ typedef struct {
   // Backward reference prefix-code histogram.
   uint32_t distance_[NUM_DISTANCE_CODES];
   int palette_code_bits_;
-  double bit_cost_;      // cached value of VP8LHistogramEstimateBits(this)
-  double literal_cost_;  // Cached values of dominant entropy costs:
-  double red_cost_;      //   literal, red & blue.
+  uint32_t trivial_symbol_;  // True, if histograms for Red, Blue & Alpha
+                             // literal symbols are single valued.
+  double bit_cost_;          // cached value of bit cost.
+  double literal_cost_;      // Cached values of dominant entropy costs:
+  double red_cost_;          // literal, red & blue.
   double blue_cost_;
 } VP8LHistogram;
 
@@ -91,14 +92,6 @@ VP8LHistogram* VP8LAllocateHistogram(int cache_bits);
 void VP8LHistogramAddSinglePixOrCopy(VP8LHistogram* const histo,
                                      const PixOrCopy* const v);
 
-// Estimate how many bits the combined entropy of literals and distance
-// approximately maps to.
-double VP8LHistogramEstimateBits(const VP8LHistogram* const p);
-
-// This function estimates the cost in bits excluding the bits needed to
-// represent the entropy code itself.
-double VP8LHistogramEstimateBitsBulk(const VP8LHistogram* const p);
-
 static WEBP_INLINE int VP8LHistogramNumCodes(int palette_code_bits) {
   return NUM_LITERAL_CODES + NUM_LENGTH_CODES +
       ((palette_code_bits > 0) ? (1 << palette_code_bits) : 0);
@@ -107,10 +100,22 @@ static WEBP_INLINE int VP8LHistogramNumCodes(int palette_code_bits) {
 // Builds the histogram image.
 int VP8LGetHistoImageSymbols(int xsize, int ysize,
                              const VP8LBackwardRefs* const refs,
-                             int quality, int histogram_bits, int cache_bits,
+                             int quality, int low_effort,
+                             int histogram_bits, int cache_bits,
                              VP8LHistogramSet* const image_in,
+                             VP8LHistogramSet* const tmp_histos,
                              uint16_t* const histogram_symbols);
 
+// Returns the entropy for the symbols in the input array.
+// Also sets trivial_symbol to the code value, if the array has only one code
+// value. Otherwise, set it to VP8L_NON_TRIVIAL_SYM.
+double VP8LBitsEntropy(const uint32_t* const array, int n,
+                       uint32_t* const trivial_symbol);
+
+// Estimate how many bits the combined entropy of literals and distance
+// approximately maps to.
+double VP8LHistogramEstimateBits(const VP8LHistogram* const p);
+
 #ifdef __cplusplus
 }
 #endif