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

net/base/sdch_dictionary_fetcher.cc

Index: net/base/sdch_dictionary_fetcher.cc
diff --git a/net/base/sdch_dictionary_fetcher.cc b/net/base/sdch_dictionary_fetcher.cc
index 3e6f590852c3ec84ec343f516ceb6c6e481133f9..4a45f107e3e8b48270ddac282525b7141ae3a819 100644
--- a/net/base/sdch_dictionary_fetcher.cc
+++ b/net/base/sdch_dictionary_fetcher.cc
@@ -204,6 +204,14 @@ int SdchDictionaryFetcher::DoRead(int rv) {
       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();
   }