Handle URLRequest::Read() returning false without an error or ERR_IO_PENDING.

net/base/sdch_dictionary_fetcher.cc

 // 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.
 
 #include "net/base/sdch_dictionary_fetcher.h"
 
 #include <stdint.h>
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
@@ skipping 185 matching lines @@
 
     return OK;
   }
 
   next_state_ = STATE_REQUEST_READING;
   int bytes_read = 0;
   if (!current_request_->Read(buffer_.get(), kBufferSize, &bytes_read)) {
     if (current_request_->status().is_io_pending())
       return ERR_IO_PENDING;
 
     DCHECK_NE(current_request_->status().error(), OK);

[Ryan Hamilton, 2014/09/23 21:38:38]

Technically, the style guide prohibits "handling" failed DCHECKs.

http://www.chromium.org/developers/coding-style#TOC-CHECK-DCHECK-and-NOTREACHED-

That would suggest using something like DLOG(DFATAL) instead.

+    if (current_request_->status().error() == OK) {
+      // This "should never happen", but if it does the result will be
+      // an infinite loop.  It's not clear how to handle a read failure
+      // without a promise to invoke the callback at some point in the future,
+      // so the request is failed.
+      SdchManager::SdchErrorRecovery(SdchManager::DICTIONARY_FETCH_READ_FAILED);
+      return ERR_FAILED;
+    }
 
     return current_request_->status().error();
   }
 
   if (bytes_read != 0)
     dictionary_.append(buffer_->data(), bytes_read);
   else
     next_state_ = STATE_REQUEST_COMPLETE;
 
   return OK;
 }
 
 int SdchDictionaryFetcher::DoCompleteRequest(int rv) {
   DCHECK(CalledOnValidThread());
 
   // If the dictionary was successfully fetched, add it to the manager.
   if (rv == OK)
     consumer_->AddSdchDictionary(dictionary_, current_request_->url());
 
   current_request_.reset();
   buffer_ = NULL;
   dictionary_.clear();
 
   next_state_ = STATE_IDLE;
 
   return OK;
 }
 
 }  // namespace net