Add DCHECKs to the states that should be entered only when the...

net/ftp/ftp_network_transaction.cc

Index: net/ftp/ftp_network_transaction.cc
===================================================================
--- net/ftp/ftp_network_transaction.cc	(revision 19253)
+++ net/ftp/ftp_network_transaction.cc	(working copy)
@@ -239,6 +239,7 @@
         rv = DoCtrlConnectComplete(rv);
         break;
       case STATE_CTRL_READ:
+        DCHECK(rv == OK);
         rv = DoCtrlRead();
         break;
       case STATE_CTRL_READ_COMPLETE:
@@ -281,19 +282,24 @@
         rv = DoCtrlWriteSIZE();
         break;
       case STATE_CTRL_WRITE_CWD:
+        DCHECK(rv == OK);
         rv = DoCtrlWriteCWD();
         break;
       case STATE_CTRL_WRITE_LIST:
+        DCHECK(rv == OK);
         rv = DoCtrlWriteLIST();
         break;
       case STATE_CTRL_WRITE_MDTM:
+        DCHECK(rv == OK);
         rv = DoCtrlWriteMDTM();
         break;
       case STATE_CTRL_WRITE_QUIT:
+        DCHECK(rv == OK);
         rv = DoCtrlWriteQUIT();
         break;
 
       case STATE_DATA_RESOLVE_HOST:
+        DCHECK(rv == OK);
         rv = DoDataResolveHost();
         break;
       case STATE_DATA_RESOLVE_HOST_COMPLETE:
@@ -307,6 +313,7 @@
         rv = DoDataConnectComplete(rv);
         break;
       case STATE_DATA_READ:
+        DCHECK(rv == OK);
         rv = DoDataRead();
         break;
       case STATE_DATA_READ_COMPLETE: