Implement missing heap-intercept function "dh_malloc_usable_size".


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@14721 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/exp-dhat/dh_main.c b/exp-dhat/dh_main.c
index 2730385..471c3ed 100644
--- a/exp-dhat/dh_main.c
+++ b/exp-dhat/dh_main.c
@@ -671,12 +671,11 @@
 
 static SizeT dh_malloc_usable_size ( ThreadId tid, void* p )
 {                                                            
-   tl_assert(0);
-//zz   HP_Chunk* hc = VG_(HT_lookup)( malloc_list, (UWord)p );
-//zz
-//zz   return ( hc ? hc->req_szB + hc->slop_szB : 0 );
+   Block* bk = find_Block_containing( (Addr)p );
+   return bk ? bk->req_szB : 0;
 }                                                            
 
+
 //------------------------------------------------------------//
 //--- memory references                                    ---//
 //------------------------------------------------------------//