Introduce HttpStream and HttpBasicStream.

Introduce HttpStream and HttpBasicStream.
This is the beginning of the http pipelining work.  Introduce HttpStream, an interface for reading and writing to http streams.  Provide a basic implementation with HttpBasicStream.  Switch HttpNetworkTransaction to reading/writing via HttpStream rather than directly to the socket.
Note that the interface will have to change later on.  Read/Write() is the wrong interface, since a pipelining HttpStream implementation will have to detect the end of an http response, rather than having the client (HttpNetworkTransaction) do that.  This is just the first step.
For information of the general roadmap for http pipelining, please refer to the bug.
BUG=http://crbug.com/8991
TEST=none

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=18199

[wtc, 2009-06-09 18:58:22]

LGTM.

Many of the things you said in the CL's description should
be moved the the header files as comments.  Right now the
two new headers have no comments at all!

http://codereview.chromium.org/119346/diff/10/1006
File net/http/http_basic_stream.h (right):

http://codereview.chromium.org/119346/diff/10/1006#newcode8
Line 8: #include "base/basictypes.h"
Is this header necessary?

http://codereview.chromium.org/119346/diff/10/1009
File net/http/http_stream.h (right):

http://codereview.chromium.org/119346/diff/10/1009#newcode15
Line 15: class HttpStream {
Please add comments to describe the HttpStream
interface and its methods.

Nit: list Read before Write.

This interface is actually identical to the Socket interface, so you should be
able to copy most of the
comments from socket.h.

[willchan no longer on Chromium, 2009-06-09 22:04:21]

http://codereview.chromium.org/119346/diff/10/1006
File net/http/http_basic_stream.h (right):

http://codereview.chromium.org/119346/diff/10/1006#newcode8
Line 8: #include "base/basictypes.h"
On 2009/06/09 18:58:22, wtc wrote:
> Is this header necessary?

Style wise, yes.  It's for DISALLOW_COPY_AND_ASSIGN.  Strictly speaking, it's
not necessary because HttpStream has the basictypes.h include too.  However, if
it's fragile for consumers to depend on transitive include dependencies.  The
Google C++ style mailing list forbids this.  There's an internal wiki on it:
http://wiki/Main/IncludeWhatYouUse.  So, I'm including what I'm using here.

http://codereview.chromium.org/119346/diff/10/1009
File net/http/http_stream.h (right):

http://codereview.chromium.org/119346/diff/10/1009#newcode15
Line 15: class HttpStream {
On 2009/06/09 18:58:22, wtc wrote:
> Please add comments to describe the HttpStream
> interface and its methods.
> 
> Nit: list Read before Write.
> 
> This interface is actually identical to the Socket interface, so you should be
> able to copy most of the
> comments from socket.h.

Done.

[eroman, 2009-06-09 22:58:46]

are their any design docs for the pipelining?

in particular i am wandering how cancellation of a transaction works when
sharing an httpstream.

otherwise LG.

http://codereview.chromium.org/119346/diff/16/1013
File net/http/http_basic_stream.h (right):

http://codereview.chromium.org/119346/diff/16/1013#newcode14
Line 14: class HttpBasicStream : public HttpStream {
a class comment would be good.