Make WebURLLoader capable of retaining received buffers.

content/public/child/request_peer.h

 // Copyright 2014 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.
 
 #ifndef CONTENT_PUBLIC_CHILD_REQUEST_PEER_H_
 #define CONTENT_PUBLIC_CHILD_REQUEST_PEER_H_
 
 #include <string>
 
 #include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
 #include "content/common/content_export.h"
 
 class GURL;
 
 namespace base {
 class TimeTicks;
 }
 
 namespace net {
 struct RedirectInfo;
 }
 
 namespace content {
 
 struct ResourceResponseInfo;
 
 // This is implemented by our custom resource loader within content. The Peer
 // and it's bridge should have identical lifetimes as they represent each end of
 // a communication channel.
 //
 // These callbacks mirror net::URLRequest::Delegate and the order and
 // conditions in which they will be called are identical. See url_request.h
 // for more information.
 class CONTENT_EXPORT RequestPeer {
  public:
+  // This class represents data gotten from the Browser process. Each data
+  // consists of |payload|, |length| and |encoded_length|. The payload is
+  // valid only when the data instance is valid.
+  // In order to work with Chrome resource loading IPC, it is desirable to
+  // reclaim data in FIFO order in a RequestPeer in terms of performance.
+  // |payload|, |length| and |encoded_length| functions are thread-safe, but
+  // the data object itself must be destroyed on the original thread.
+  class CONTENT_EXPORT ReceivedData {
+   public:
+    virtual ~ReceivedData() {}
+    virtual const char* payload() const = 0;
+    virtual int length() const = 0;
+    // The encoded_length is the length of the encoded data transferred
+    // over the network, which could be different from data length (e.g. for
+    // gzipped content).
+    virtual int encoded_length() const = 0;
+  };
+
   // Called as upload progress is made.
   // note: only for requests with upload progress enabled.
   virtual void OnUploadProgress(uint64 position, uint64 size) = 0;
 
   // Called when a redirect occurs.  The implementation may return false to
   // suppress the redirect.  The ResourceResponseInfo provides information about
   // the redirect response and the RedirectInfo includes information about the
   // request to be made if the method returns true.
   virtual bool OnReceivedRedirect(const net::RedirectInfo& redirect_info,
                                   const ResourceResponseInfo& info) = 0;
 
   // Called when response headers are available (after all redirects have
   // been followed).
   virtual void OnReceivedResponse(const ResourceResponseInfo& info) = 0;
 
   // Called when a chunk of response data is downloaded.  This method may be
   // called multiple times or not at all if an error occurs.  This method is
   // only called if RequestInfo::download_to_file was set to true, and in
   // that case, OnReceivedData will not be called.
   // The encoded_data_length is the length of the encoded data transferred
   // over the network, which could be different from data length (e.g. for
   // gzipped content).
   virtual void OnDownloadedData(int len, int encoded_data_length) = 0;
 
   // Called when a chunk of response data is available. This method may
   // be called multiple times or not at all if an error occurs.
-  // The encoded_data_length is the length of the encoded data transferred
-  // over the network, which could be different from data length (e.g. for
-  // gzipped content).
-  virtual void OnReceivedData(const char* data,
-                              int data_length,
-                              int encoded_data_length) = 0;
+  virtual void OnReceivedData(scoped_ptr<ReceivedData> data) = 0;
 
   // Called when metadata generated by the renderer is retrieved from the
   // cache. This method may be called zero or one times.
   virtual void OnReceivedCachedMetadata(const char* data, int len) {}
 
   // Called when the response is complete.  This method signals completion of
   // the resource load.
   virtual void OnCompletedRequest(int error_code,
                                   bool was_ignored_by_handler,
                                   bool stale_copy_in_cache,
                                   const std::string& security_info,
                                   const base::TimeTicks& completion_time,
                                   int64 total_transfer_size) = 0;
 
  protected:
   virtual ~RequestPeer() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_CHILD_REQUEST_PEER_H_