downloads: Improve download rate estimation.

content/browser/download/base_file.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 "content/browser/download/base_file.h"
 
 #include "base/bind.h"
 #include "base/file_util.h"
 #include "base/format_macros.h"
 #include "base/logging.h"
@@ skipping 119 matching lines @@
       if (write_result < 0)
         return LogNetError("Write", static_cast<net::Error>(write_result));
     }
 
     // Update status.
     size_t write_size = static_cast<size_t>(write_result);
     DCHECK_LE(write_size, len);
     len -= write_size;
     current_data += write_size;
     bytes_so_far_ += write_size;
+    rate_estimator_.AddBytes(write_size);
   }
 
   RecordDownloadWriteSize(data_len);
   RecordDownloadWriteLoopCount(write_count);
 
   if (calculate_hash_)
     secure_hash_->Update(data, data_len);
 
   return DOWNLOAD_INTERRUPT_REASON_NONE;
 }
@@ skipping 183 matching lines @@
 }
 
 void BaseFile::ClearStream() {
   // This should only be called when we have a stream.
   DCHECK(file_stream_.get() != NULL);
   file_stream_.reset();
   bound_net_log_.EndEvent(net::NetLog::TYPE_DOWNLOAD_FILE_OPENED);
 }
 
 int64 BaseFile::CurrentSpeedAtTime(base::TimeTicks current_time) const {
-  base::TimeDelta diff = current_time - start_tick_;
-  int64 diff_ms = diff.InMilliseconds();
-  return diff_ms == 0 ? 0 : bytes_so_far() * 1000 / diff_ms;
+  return rate_estimator_.GetBytesPerSecond();
 }
 
 DownloadInterruptReason BaseFile::LogNetError(
     const char* operation,
     net::Error error) {
   bound_net_log_.AddEvent(
       net::NetLog::TYPE_DOWNLOAD_FILE_ERROR,
       base::Bind(&FileErrorNetLogCallback, operation, error));
   return ConvertNetErrorToInterruptReason(error, DOWNLOAD_INTERRUPT_FROM_DISK);
 }
@@ skipping 13 matching lines @@
     const char* operation,
     int os_error,
     DownloadInterruptReason reason) {
   bound_net_log_.AddEvent(
       net::NetLog::TYPE_DOWNLOAD_FILE_ERROR,
       base::Bind(&FileInterruptedNetLogCallback, operation, os_error, reason));
   return reason;
 }
 
 }  // namespace content