Fix size_t truncations in net for 64-bit VS 2015

net/server/web_socket_encoder.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/server/web_socket_encoder.h"
 
 #include <vector>
 
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 131 matching lines @@
                        int masking_key,
                        bool compressed,
                        std::string* output) {
   std::vector<char> frame;
   OpCode op_code = kOpCodeText;
   size_t data_length = message.length();
 
   int reserved1 = compressed ? kReserved1Bit : 0;
   frame.push_back(kFinalBit | op_code | reserved1);
   char mask_key_bit = masking_key != 0 ? kMaskBit : 0;
-  if (data_length <= kMaxSingleBytePayloadLength)
-    frame.push_back(data_length | mask_key_bit);
-  else if (data_length <= 0xFFFF) {
+  if (data_length <= kMaxSingleBytePayloadLength) {
+    frame.push_back(static_cast<char>(data_length) | mask_key_bit);
+  } else if (data_length <= 0xFFFF) {
     frame.push_back(kTwoBytePayloadLengthField | mask_key_bit);
     frame.push_back((data_length & 0xFF00) >> 8);
     frame.push_back(data_length & 0xFF);
   } else {
     frame.push_back(kEightBytePayloadLengthField | mask_key_bit);
     char extended_payload_length[8];
     size_t remaining = data_length;
     // Fill the length into extended_payload_length in the network byte order.
     for (int i = 0; i < 8; ++i) {
       extended_payload_length[7 - i] = remaining & 0xFF;
@@ skipping 176 matching lines @@
     return false;
   scoped_refptr<IOBufferWithSize> buffer =
       deflater_->GetOutput(deflater_->CurrentOutputSize());
   if (!buffer.get())
     return false;
   *output = std::string(buffer->data(), buffer->size());
   return true;
 }
 
 }  // namespace net