Add step OverAwait to service protocol

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 0ab4ee2f7aaa5f77ba1cc8f5aaba3c8a5108001e..57aabfb7512aa8b0727b06baad299dec8585cbb3 100644
--- a/runtime/vm/service/service.md
+++ b/runtime/vm/service/service.md
@@ -919,6 +919,10 @@ class Breakpoint extends Object {
   // Has this breakpoint been assigned to a specific program location?
   bool resolved;
 
+  // Is this a breakpoint that was added synthetically as part of a step
+  // OverAsyncSuspension resume command?
+  bool isSyntheticAsyncContinuation [optional].
+
   // SourceLocation when breakpoint is resolved, UnresolvedSourceLocation
   // when a breakpoint is not resolved.
   SourceLocation|UnresolvedSourceLocation location;
@@ -1208,6 +1212,13 @@ class Event extends Response {
   //
   // This is provided for the Extension event.
   ExtensionData extensionData [optional];
+
+  // Is the isolate paused at an await, yield, or yield* statement?
+  //
+  // This is provided for the event kinds:
+  //   PauseBreakpoint
+  //   PauseInterrupted
+  bool atAsyncSuspension [optional]
 }
 ```
 
@@ -2333,6 +2344,7 @@ is thrown.
 enum StepOption {
   Into,
   Over,
+  OverAsyncSuspension,
   Out
 }
 ```
@@ -2475,6 +2487,6 @@ version | comments
 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.  The getObject RPC now accepts offset and count for string objects.  String objects now contain length, offset, and count properties.
 3.2 | Isolate objects now include the runnable bit and many debugger related RPCs will return an error if executed on an isolate before it is runnable.
-
+3.3 | Pause event now indicates if the isolate is paused at an await, yield, or yield* suspension point via the 'atAsyncSuspension' field. Resume command now supports the step parameter 'OverAsyncSuspension'. A Breakpoint added synthetically by an 'OverAsyncSuspension' resume command identifies itself as such via the 'isSyntheticAsyncContinuation' field.
 
 [discuss-list]: https://groups.google.com/a/dartlang.org/forum/#!forum/observatory-discuss