Revert a workaround commit for a Use-After-Free crash.

Revert a workaround commit r20158 for a Use-After-Free issue (http://crbug.com/244746) because a cleaner CL r207218 is landed.
URLRequestContext does not inherit SupportsWeakPtr now.

R=mmenke
BUG=244746

Review URL: https://chromiumcodereview.appspot.com/16870008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@207811 0039d316-1c4b-4281-b951-d872f2087c98
int SocketStream::DoReadTunnelHeaders() {
  DCHECK_EQ(kTunnelProxy, proxy_mode_);

  next_state_ = STATE_READ_TUNNEL_HEADERS_COMPLETE;

  if (!tunnel_response_headers_.get()) {
    tunnel_response_headers_ = new ResponseHeaders();
    tunnel_response_headers_capacity_ = kMaxTunnelResponseHeadersSize;
    tunnel_response_headers_->Realloc(tunnel_response_headers_capacity_);
    tunnel_response_headers_len_ = 0;
  }

  int buf_len = tunnel_response_headers_capacity_ -
      tunnel_response_headers_len_;
  tunnel_response_headers_->SetDataOffset(tunnel_response_headers_len_);
  CHECK(tunnel_response_headers_->data());

  return socket_->Read(tunnel_response_headers_.get(), buf_len, io_callback_);
}

int SocketStream::DoReadTunnelHeaders() {
  DCHECK_EQ(kTunnelProxy, proxy_mode_);

  next_state_ = STATE_READ_TUNNEL_HEADERS_COMPLETE;

  if (!tunnel_response_headers_.get()) {
    tunnel_response_headers_ = new ResponseHeaders();
    tunnel_response_headers_capacity_ = kMaxTunnelResponseHeadersSize;
    tunnel_response_headers_->Realloc(tunnel_response_headers_capacity_);
    tunnel_response_headers_len_ = 0;
  }

  int buf_len = tunnel_response_headers_capacity_ -
      tunnel_response_headers_len_;
  tunnel_response_headers_->SetDataOffset(tunnel_response_headers_len_);
  CHECK(tunnel_response_headers_->data());

  return socket_->Read(tunnel_response_headers_.get(), buf_len, io_callback_);
}
