Minor cleanup in SpdyFrameBuilder. No functional/compiled change.

net/spdy/spdy_frame_reader.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 <limits>
 
 #include "base/sys_byteorder.h"
 #include "net/spdy/spdy_frame_reader.h"
 #include "net/spdy/spdy_protocol.h"
 
@@ skipping 51 matching lines @@
   ofs_ += 4;
 
   return true;
 }
 
 bool SpdyFrameReader::ReadUInt31(uint32* result) {
   bool success = ReadUInt32(result);
 
   // Zero out highest-order bit.
   if (success) {
-    *result &= kStreamIdMask;
+    *result &= 0x7fffffff;
   }
 
   return success;
 }
 
 bool SpdyFrameReader::ReadStringPiece16(base::StringPiece* result) {
   // Read resultant length.
   uint16 result_len;
   if (!ReadUInt16(&result_len)) {
     // OnFailure() already called.
@@ skipping 74 matching lines @@
   return bytes <= (len_ - ofs_);
 }
 
 void SpdyFrameReader::OnFailure() {
   // Set our iterator to the end of the buffer so that further reads fail
   // immediately.
   ofs_ = len_;
 }
 
 }  // namespace net