Implement DDMS heap info ("HPIF") chunks.

This lets you see how many bytes/objects are in your managed heap.

Change-Id: Ie925207e9c48989a24968633e60b99314d220865
diff --git a/src/jdwp/jdwp_handler.cc b/src/jdwp/jdwp_handler.cc
index f408c54..04c4734 100644
--- a/src/jdwp/jdwp_handler.cc
+++ b/src/jdwp/jdwp_handler.cc
@@ -1806,7 +1806,7 @@
    * the initial setup.  Only update if this is a non-DDMS packet.
    */
   if (pHeader->cmdSet != kJDWPDdmCmdSet) {
-    QuasiAtomicSwap64(GetNowMsec(), &lastActivityWhen);
+    QuasiAtomicSwap64(MilliTime(), &lastActivityWhen);
   }
 
   /* tell the VM that GC is okay again */