libwebp: update to v0.5.1

third_party/libwebp/dec/webp.c

Index: third_party/libwebp/dec/webp.c
diff --git a/third_party/libwebp/dec/webp.c b/third_party/libwebp/dec/webp.c
index 78220433777f69f12d11d84f428f0ee964ab4c1c..90d8a45d230ff94d0c29452874581b49a7ba2e61 100644
--- a/third_party/libwebp/dec/webp.c
+++ b/third_party/libwebp/dec/webp.c
@@ -403,7 +403,8 @@ static VP8StatusCode ParseHeadersInternal(const uint8_t* data,
 }
 
 VP8StatusCode WebPParseHeaders(WebPHeaderStructure* const headers) {
-  VP8StatusCode status;
+  // status is marked volatile as a workaround for a clang-3.8 (aarch64) bug
+  volatile VP8StatusCode status;
   int has_animation = 0;
   assert(headers != NULL);
   // fill out headers, ignore width/height/has_alpha.
@@ -500,10 +501,12 @@ static VP8StatusCode DecodeInto(const uint8_t* const data, size_t data_size,
 
   if (status != VP8_STATUS_OK) {
     WebPFreeDecBuffer(params->output);
-  }
-
-  if (params->options != NULL && params->options->flip) {
-    status = WebPFlipBuffer(params->output);
+  } else {
+    if (params->options != NULL && params->options->flip) {
+      // This restores the original stride values if options->flip was used
+      // during the call to WebPAllocateDecBuffer above.
+      status = WebPFlipBuffer(params->output);
+    }
   }
   return status;
 }
@@ -746,9 +749,24 @@ VP8StatusCode WebPDecode(const uint8_t* data, size_t data_size,
   }
 
   WebPResetDecParams(&params);
-  params.output = &config->output;
   params.options = &config->options;
-  status = DecodeInto(data, data_size, &params);
+  params.output = &config->output;
+  if (WebPAvoidSlowMemory(params.output, &config->input)) {
+    // decoding to slow memory: use a temporary in-mem buffer to decode into.
+    WebPDecBuffer in_mem_buffer;
+    WebPInitDecBuffer(&in_mem_buffer);
+    in_mem_buffer.colorspace = config->output.colorspace;
+    in_mem_buffer.width = config->input.width;
+    in_mem_buffer.height = config->input.height;
+    params.output = &in_mem_buffer;
+    status = DecodeInto(data, data_size, &params);
+    if (status == VP8_STATUS_OK) {  // do the slow-copy
+      status = WebPCopyDecBufferPixels(&in_mem_buffer, &config->output);
+    }
+    WebPFreeDecBuffer(&in_mem_buffer);
+  } else {
+    status = DecodeInto(data, data_size, &params);
+  }
 
   return status;
 }
@@ -797,7 +815,7 @@ int WebPIoInitFromOptions(const WebPDecoderOptions* const options,
   }
 
   // Filter
-  io->bypass_filtering = options && options->bypass_filtering;
+  io->bypass_filtering = (options != NULL) && options->bypass_filtering;
 
   // Fancy upsampler
 #ifdef FANCY_UPSAMPLING
@@ -814,4 +832,3 @@ int WebPIoInitFromOptions(const WebPDecoderOptions* const options,
 }
 
 //------------------------------------------------------------------------------
-