21723. a=chofmann, r=warren. earlier this week segment size and max size parameters were exposed to higher level consumers of necko apis. this change warns a user if they try to create a pipe w/ zero len segs and max sizes. pipes are useless without sizes

xpcom/io/nsPipe2.cpp

@@ -792,6 +792,8 @@ NS_NewPipe(nsIBufferInputStream* *inStrResult,
            PRUint32 maxSize)
 {
     nsresult rv;
+    NS_ASSERTION(segmentSize > 0, "need to supply segmentSize for buffer");
+    NS_ASSERTION(maxSize > 0, "need to supply maxSize for buffer");
     const nsCID* cid = &kAllocatorCID;
 #ifdef PAGE_MANAGER
     // Take the page manager out altogether because some unices don't