libwebp: update snapshot to v0.3.0-rc6

third_party/libwebp/enc/cost.c

 // Copyright 2011 Google Inc. All Rights Reserved.
 //
 // This code is licensed under the same terms as WebM:
 //  Software License Agreement:  http://www.webmproject.org/license/software/
 //  Additional IP Rights Grant:  http://www.webmproject.org/license/additional/
 // -----------------------------------------------------------------------------
 //
 // Cost tables for level and modes
 //
 // Author: Skal (pascal.massimino@gmail.com)
@@ skipping 336 matching lines @@
     pattern >>= 1;
   }
   return cost;
 }
 
 //------------------------------------------------------------------------------
 // Pre-calc level costs once for all
 
 void VP8CalculateLevelCosts(VP8Proba* const proba) {
   int ctype, band, ctx;
+
+  if (!proba->dirty_) return;  // nothing to do.
+
   for (ctype = 0; ctype < NUM_TYPES; ++ctype) {
     for (band = 0; band < NUM_BANDS; ++band) {
       for(ctx = 0; ctx < NUM_CTX; ++ctx) {
         const uint8_t* const p = proba->coeffs_[ctype][band][ctx];
         uint16_t* const table = proba->level_cost_[ctype][band][ctx];
         const int cost_base = VP8BitCost(1, p[1]);
         int v;
         table[0] = VP8BitCost(0, p[1]);
         for (v = 1; v <= MAX_VARIABLE_LEVEL; ++v) {
           table[v] = cost_base + VariableLevelCost(v, p);
         }
         // Starting at level 67 and up, the variable part of the cost is
         // actually constant.
       }
     }
   }
+  proba->dirty_ = 0;
 }
 
 //------------------------------------------------------------------------------
 // Mode cost tables.
 
 // These are the fixed probabilities (in the coding trees) turned into bit-cost
 // by calling VP8BitCost().
 const uint16_t VP8FixedCostsUV[4] = { 302, 984, 439, 642 };
 // note: these values include the fixed VP8BitCost(1, 145) mode selection cost.
 const uint16_t VP8FixedCostsI16[4] = { 663, 919, 872, 919 };
@@ skipping 98 matching lines @@
     {  439, 1139, 1101, 1257, 3710, 1922, 1205, 1040, 1931, 1529 },
     {  979,  935, 1269,  847, 1202, 1286, 1530, 1535,  827, 1036 },
     {  516, 1378, 1569, 1110, 1798, 1798, 1198, 2199, 1543,  712 } },
 };
 
 //------------------------------------------------------------------------------
 
 #if defined(__cplusplus) || defined(c_plusplus)
 }    // extern "C"
 #endif