Change HpackHuffmanDecoder::CanonicalToSource() return type.

net/spdy/core/hpack/hpack_huffman_decoder.cc

Index: net/spdy/core/hpack/hpack_huffman_decoder.cc
diff --git a/net/spdy/core/hpack/hpack_huffman_decoder.cc b/net/spdy/core/hpack/hpack_huffman_decoder.cc
index 3e2fc9c2f9028bd4308dcd2aa6dffac64145f0cd..85135795dfb16054db7ca9bb431e3dd637daf569 100644
--- a/net/spdy/core/hpack/hpack_huffman_decoder.cc
+++ b/net/spdy/core/hpack/hpack_huffman_decoder.cc
@@ -292,9 +292,9 @@ HuffmanWord HpackHuffmanDecoder::DecodeToCanonical(
   return first_canonical + ordinal_in_length;
 }
 
-char HpackHuffmanDecoder::CanonicalToSource(HuffmanWord canonical) {
+uint8_t HpackHuffmanDecoder::CanonicalToSource(HuffmanWord canonical) {
   DCHECK_LT(canonical, 256u);
-  return static_cast<char>(kCanonicalToSymbol[canonical]);
+  return kCanonicalToSymbol[canonical];
 }
 
 // TODO(jamessynge): Maybe further refactorings, including just passing in a