libwebp: update to 0.5.0

third_party/libwebp/utils/rescaler.h

Index: third_party/libwebp/utils/rescaler.h
diff --git a/third_party/libwebp/utils/rescaler.h b/third_party/libwebp/utils/rescaler.h
index 8244cfeb41f194a8e2271006c829b398499bf24d..98b01a76d077dd775e5f8d86f33c7ddf80c4c405 100644
--- a/third_party/libwebp/utils/rescaler.h
+++ b/third_party/libwebp/utils/rescaler.h
@@ -20,9 +20,15 @@ extern "C" {
 
 #include "../webp/types.h"
 
+#define WEBP_RESCALER_RFIX 32   // fixed-point precision for multiplies
+#define WEBP_RESCALER_ONE (1ull << WEBP_RESCALER_RFIX)
+#define WEBP_RESCALER_FRAC(x, y) \
+    ((uint32_t)(((uint64_t)(x) << WEBP_RESCALER_RFIX) / (y)))
+
 // Structure used for on-the-fly rescaling
 typedef uint32_t rescaler_t;   // type for side-buffer
-typedef struct {
+typedef struct WebPRescaler WebPRescaler;
+struct WebPRescaler {
   int x_expand;               // true if we're expanding in the x direction
   int y_expand;               // true if we're expanding in the y direction
   int num_channels;           // bytes to jump between pixels
@@ -38,7 +44,7 @@ typedef struct {
   uint8_t* dst;
   int dst_stride;
   rescaler_t* irow, *frow;    // work buffer
-} WebPRescaler;
+};
 
 // Initialize a rescaler given scratch area 'work' and dimensions of src & dst.
 void WebPRescalerInit(WebPRescaler* const rescaler,
@@ -48,6 +54,14 @@ void WebPRescalerInit(WebPRescaler* const rescaler,
                       int num_channels,
                       rescaler_t* const work);
 
+// If either 'scaled_width' or 'scaled_height' (but not both) is 0 the value
+// will be calculated preserving the aspect ratio, otherwise the values are
+// left unmodified. Returns true on success, false if either value is 0 after
+// performing the scaling calculation.
+int WebPRescalerGetScaledDimensions(int src_width, int src_height,
+                                    int* const scaled_width,
+                                    int* const scaled_height);
+
 // Returns the number of input lines needed next to produce one output line,
 // considering that the maximum available input lines are 'max_num_lines'.
 int WebPRescaleNeededLines(const WebPRescaler* const rescaler,
@@ -60,10 +74,6 @@ int WebPRescalerImport(WebPRescaler* const rescaler, int num_rows,
 
 // Export as many rows as possible. Return the numbers of rows written.
 int WebPRescalerExport(WebPRescaler* const rescaler);
-void WebPRescalerImportRow(WebPRescaler* const wrk,
-                           const uint8_t* src);
-// Export one row (starting at x_out position) from rescaler.
-void WebPRescalerExportRow(WebPRescaler* const wrk);
 
 // Return true if input is finished
 static WEBP_INLINE