landing patch for bug 234864 "string branch landing resulted in large spike in heap allocations (brad:A metric)" r+sr=dbaron

this patch also introduces nsTFixedString and removes CBufDescriptor.


git-svn-id: svn://10.0.0.236/trunk@152994 18797224-902f-48f8-a5cc-f745e15eee43

mozilla/xpcom/string/src/nsSubstring.cpp

@@ -69,6 +69,12 @@ class nsStringStats
 
       ~nsStringStats()
         {
+          // this is a hack to suppress duplicate string stats printing
+          // in seamonkey as a result of the string code being linked
+          // into seamonkey and libxpcom! :-(
+          if (!mAllocCount && !mAdoptCount)
+            return;
+
           printf("nsStringStats\n");
           printf(" => mAllocCount: %d\n", mAllocCount);
           printf(" => mReallocCount: %d\n", mReallocCount);