Sparse IO: Allow failover to network in debug builds

net/http/http_cache_transaction.cc

Index: net/http/http_cache_transaction.cc
diff --git a/net/http/http_cache_transaction.cc b/net/http/http_cache_transaction.cc
index cd3be51cb85e011beb11c1b85b7c9257d136d922..9f341b0b4340f6d4841f506165bfbb11144f0117 100644
--- a/net/http/http_cache_transaction.cc
+++ b/net/http/http_cache_transaction.cc
@@ -1530,7 +1530,8 @@ int HttpCache::Transaction::DoCacheQueryData() {
 }
 
 int HttpCache::Transaction::DoCacheQueryDataComplete(int result) {
-  DCHECK_EQ(OK, result);
+  // Note: a backend may not support Sparse IO, in this case it is expected that
+  // header validation will fail and transition to STATE_SEND_REQUEST.

[rvargas (doing something else), 2013/08/23 17:54:13]

I would prefer if you return a specific error code from the backend and do an
explicit transition to whatever you need here.

[pasko, 2013/08/26 15:42:51]

Done.

   if (!cache_.get())
     return ERR_UNEXPECTED;