getObject now supports specifying offset,count for strings.

runtime/vm/service/service.md

Index: runtime/vm/service/service.md
diff --git a/runtime/vm/service/service.md b/runtime/vm/service/service.md
index 8a796712a70b3fbad342f30fffeae212939b12d9..bba52520c99eba712a69ac8db2fbc81a0dd763fc 100644
--- a/runtime/vm/service/service.md
+++ b/runtime/vm/service/service.md
@@ -556,7 +556,7 @@ If the object handle has not expired and the object has not been
 collected, then an [Object](#object) will be returned.
 
 The _offset_ and _count_ parameters are used to request subranges of
-Instance objects with the kinds: List, Map, Uint8ClampedList,
+Instance objects with the kinds: String, List, Map, Uint8ClampedList,
 Uint8List, Uint16List, Uint32List, Uint64List, Int8List, Int16List,
 Int32List, Int64List, Flooat32List, Float64List, Inst32x3List,
 Float32x4List, and Float64x2List.  These parameters are otherwise
@@ -1471,11 +1471,15 @@ class @Instance extends @Object {
 
   // The valueAsString for String references may be truncated. If so,
   // this property is added with the value 'true'.
+  //
+  // New code should use 'length' and 'count' instead.
   bool valueAsStringIsTruncated [optional];
 
-  // The length of a List or the number of associations in a Map.
+  // The length of a List or the number of associations in a Map or the
+  // number of codeunits in a String.
   //
   // Provided for instance kinds:
+  //   String
   //   List
   //   Map
   //   Uint8ClampedList
@@ -1544,11 +1548,15 @@ class Instance extends Object {
 
   // The valueAsString for String references may be truncated. If so,
   // this property is added with the value 'true'.
+  //
+  // New code should use 'length' and 'count' instead.
   bool valueAsStringIsTruncated [optional];
 
-  // The length of a List or the number of associations in a Map.
+  // The length of a List or the number of associations in a Map or the
+  // number of codeunits in a String.
   //
   // Provided for instance kinds:
+  //   String
   //   List
   //   Map
   //   Uint8ClampedList
@@ -1567,10 +1575,11 @@ class Instance extends Object {
   //   Float64x2List
   int length [optional];
 
-  // The index of the first element or association returned.
+  // The index of the first element or association or codeunit returned.
   // This is only provided when it is non-zero.
   //
   // Provided for instance kinds:
+  //   String
   //   List
   //   Map
   //   Uint8ClampedList
@@ -1589,10 +1598,11 @@ class Instance extends Object {
   //   Float64x2List
   int offset [optional];
 
-  // The number of elements or associations returned.
+  // The number of elements or associations or codeunits returned.
   // This is only provided when it is less than length.
   //
   // Provided for instance kinds:
+  //   String
   //   List
   //   Map
   //   Uint8ClampedList
@@ -2460,7 +2470,7 @@ version | comments
 1.0 | initial revision
 2.0 | Describe protocol version 2.0.
 3.0 | Describe protocol version 3.0.  Added UnresolvedSourceLocation.  Added Sentinel return to getIsolate.  Add AddedBreakpointWithScriptUri.  Removed Isolate.entry. The type of VM.pid was changed from string to int.  Added VMUpdate events.  Add offset and count parameters to getObject() and offset and count fields to Instance. Added ServiceExtensionAdded event.
-3.1 | Add the getSourceReport RPC.
+3.1 | Add the getSourceReport RPC.  The getObject RPC now accepts offset and count for string objects.  String objects now contain length, offset, and count properties.
 
 
 [discuss-list]: https://groups.google.com/a/dartlang.org/forum/#!forum/observatory-discuss