Switch to using SourceLocation universally in service protocol.

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

Index: runtime/observatory/lib/src/elements/isolate_view.dart
diff --git a/runtime/observatory/lib/src/elements/isolate_view.dart b/runtime/observatory/lib/src/elements/isolate_view.dart
index 766f2874d781ad7ec2c96f6a6ff442868c05d971..fc6116b4a78b173d9e14de67e2b03af7ee4e8a40 100644
--- a/runtime/observatory/lib/src/elements/isolate_view.dart
+++ b/runtime/observatory/lib/src/elements/isolate_view.dart
@@ -103,6 +103,9 @@ class IsolateViewElement extends ObservatoryElement {
     super.attached();
     // Start a timer to update the isolate summary once a second.
     _updateTimer = new Timer(new Duration(seconds: 1), _updateTagProfile);
+    if (isolate.topFrame != null) {
+      isolate.topFrame.function.load();
+    }
   }
 
   @override
@@ -121,8 +124,11 @@ class IsolateViewElement extends ObservatoryElement {
     }
   }
 
-  Future refresh() {
-    return isolate.reload();
+  Future refresh() async {
+    await isolate.reload();
+    if (isolate.topFrame != null) {
+      await isolate.topFrame.function.load();
+    }
   }
 
   Future refreshCoverage() {