Update HTTP/2 DATA frame padding to 0x00.

net/spdy/spdy_framer.cc

 // Copyright (c) 2012 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/spdy/spdy_framer.h"
 
 #include "base/lazy_instance.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/metrics/stats_counters.h"
 #include "base/third_party/valgrind/memcheck.h"
@@ skipping 2296 matching lines @@
     const size_t size_with_padding = num_padding_fields +
         data_ir.data().length() + data_ir.padding_payload_len() +
         GetDataFrameMinimumSize();
     SpdyFrameBuilder builder(size_with_padding, protocol_version());
     builder.WriteDataFrameHeader(*this, data_ir.stream_id(), flags);
     if (data_ir.padded()) {
       builder.WriteUInt8(data_ir.padding_payload_len() & 0xff);
     }
     builder.WriteBytes(data_ir.data().data(), data_ir.data().length());
     if (data_ir.padding_payload_len() > 0) {
-      string padding = string(data_ir.padding_payload_len(), '0');
+      string padding(data_ir.padding_payload_len(), 0);
       builder.WriteBytes(padding.data(), padding.length());
     }
     DCHECK_EQ(size_with_padding, builder.length());
     return builder.take();
   } else {
     const size_t size = GetDataFrameMinimumSize() + data_ir.data().length();
     SpdyFrameBuilder builder(size, protocol_version());
     builder.WriteDataFrameHeader(*this, data_ir.stream_id(), flags);
     builder.WriteBytes(data_ir.data().data(), data_ir.data().length());
     DCHECK_EQ(size, builder.length());
@@ skipping 915 matching lines @@
   builder->Seek(compressed_size);
   builder->RewriteLength(*this);
 
   pre_compress_bytes.Add(uncompressed_len);
   post_compress_bytes.Add(compressed_size);
 
   compressed_frames.Increment();
 }
 
 }  // namespace net