AU: HttpFetcher: Fix segfault with multi fetcher and small transfers

multi_range_http_fetcher.cc

 // Copyright (c) 2010 The Chromium OS 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 "update_engine/multi_range_http_fetcher.h"
 
 #include "update_engine/utils.h"
 
 namespace chromeos_update_engine {
 
@@ skipping 105 matching lines @@
       Reset();
       // Note that after the callback returns this object may be destroyed.
       if (delegate_)
         delegate_->TransferComplete(this, false);
       return;
     }
     // We got enough bytes and there were bytes specified, so this is success.
     successful = true;
   }
 
-  // If we have another fetcher, use that.
+  // If we have another transfer, do that.
   if (current_index_ + 1 < ranges_.size()) {
     current_index_++;
     LOG(INFO) << "Starting next transfer (" << current_index_ << ").";
     StartTransfer();
     return;
   }
 
   LOG(INFO) << "Done w/ all transfers";
   Reset();
   // Note that after the callback returns this object may be destroyed.
@@ skipping 12 matching lines @@
   TransferEnded(fetcher, false);
 }
 
 void MultiRangeHTTPFetcher::Reset() {
   base_fetcher_active_ = pending_transfer_ended_ = terminating_ = false;
   current_index_ = 0;
   bytes_received_this_range_ = 0;
 }
 
 }  // namespace chromeos_update_engine