Make several service protocol RPCs private.

runtime/observatory/lib/src/elements/heap_map.dart

Index: runtime/observatory/lib/src/elements/heap_map.dart
diff --git a/runtime/observatory/lib/src/elements/heap_map.dart b/runtime/observatory/lib/src/elements/heap_map.dart
index 631b7801a58e9d1db43b731862ffc7063ab9da42..7b7be4fbc8d4651285e4f57fb476c3df98a6b62e 100644
--- a/runtime/observatory/lib/src/elements/heap_map.dart
+++ b/runtime/observatory/lib/src/elements/heap_map.dart
@@ -224,7 +224,7 @@ class HeapMapElement extends ObservatoryElement {
       fragmentation = null;
       return;
     }
-    isolate.invokeRpc('getHeapMap', {}).then((ServiceMap response) {
+    isolate.invokeRpc('_getHeapMap', {}).then((ServiceMap response) {
       assert(response['type'] == 'HeapMap');
       fragmentation = response;
     }).catchError((e, st) {
@@ -236,7 +236,7 @@ class HeapMapElement extends ObservatoryElement {
     if (isolate == null) {
       return new Future.value(null);
     }
-    return isolate.invokeRpc('getHeapMap', {}).then((ServiceMap response) {
+    return isolate.invokeRpc('_getHeapMap', {}).then((ServiceMap response) {
       assert(response['type'] == 'HeapMap');
       fragmentation = response;
     });