net: Introduce SeekableIOBuffer and clean up HttpStreamParser.

net/http/http_stream_parser.cc

Index: net/http/http_stream_parser.cc
diff --git a/net/http/http_stream_parser.cc b/net/http/http_stream_parser.cc
index b85a342dda979f2bb178024d63ebd18535217112..1b1f02aad77bf1f7c39c3590602632635bdc0ce8 100644
--- a/net/http/http_stream_parser.cc
+++ b/net/http/http_stream_parser.cc
@@ -128,10 +128,10 @@ int HttpStreamParser::SendRequest(const std::string& request_line,
   request_body_.reset(request_body);
   if (request_body_ != NULL && request_body_->is_chunked()) {
     request_body_->set_chunk_callback(this);
-    // The raw chunk buffer is guaranteed to be large enough to hold the
-    // encoded chunk.
-    raw_chunk_buf_ = new IOBufferWithSize(UploadDataStream::GetBufferSize() +
-                                          kChunkHeaderFooterSize);
+    // The chunk buffer is guaranteed to be large enough to hold the encoded
+    // chunk.
+    chunk_buf_ = new SeekableIOBuffer(UploadDataStream::GetBufferSize() +
+                                      kChunkHeaderFooterSize);
   }
 
   io_state_ = STATE_SENDING_HEADERS;
@@ -349,13 +349,11 @@ int HttpStreamParser::DoSendChunkedBody(int result) {
   // DoSendChunkedBody(), or 0 (i.e. OK) the first time.
 
   // Send the remaining data in the chunk buffer.
-  if (chunk_buf_.get()) {
-    chunk_buf_->DidConsume(result);
-    if (chunk_buf_->BytesRemaining() > 0) {
-      return connection_->socket()->Write(chunk_buf_,
-                                          chunk_buf_->BytesRemaining(),
-                                          io_callback_);
-    }
+  chunk_buf_->DidConsume(result);
+  if (chunk_buf_->BytesRemaining() > 0) {
+    return connection_->socket()->Write(chunk_buf_,
+                                        chunk_buf_->BytesRemaining(),
+                                        io_callback_);
   }
 
   if (sent_last_chunk_) {
@@ -369,17 +367,19 @@ int HttpStreamParser::DoSendChunkedBody(int result) {
   chunk_length_without_encoding_ = 0;
 
   if (request_body_->eof()) {
+    chunk_buf_->Clear();
     const int chunk_length = EncodeChunk(
-        base::StringPiece(), raw_chunk_buf_->data(), raw_chunk_buf_->size());
-    chunk_buf_ = new DrainableIOBuffer(raw_chunk_buf_, chunk_length);
+        base::StringPiece(), chunk_buf_->data(), chunk_buf_->capacity());
+    chunk_buf_->DidAppend(chunk_length);
     sent_last_chunk_ = true;
   } else if (request_body_->buf_len() > 0) {
     // Encode and send the buffer as 1 chunk.
     const base::StringPiece payload(request_body_->buf()->data(),
                                     request_body_->buf_len());
+    chunk_buf_->Clear();
     const int chunk_length = EncodeChunk(
-        payload, raw_chunk_buf_->data(), raw_chunk_buf_->size());
-    chunk_buf_ = new DrainableIOBuffer(raw_chunk_buf_, chunk_length);
+        payload, chunk_buf_->data(), chunk_buf_->capacity());
+    chunk_buf_->DidAppend(chunk_length);
     chunk_length_without_encoding_ = payload.size();
   } else {
     // Nothing to send. More POST data is yet to come?