[ dart:developer ] Updated parentId argument for timeline events to use base64 to be consistent with async ID formatting

Change-Id: I96314f5712b722da5188c0a447a12c9c5fe6064b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/120322
Reviewed-by: Kenzie Schmoll <kenzieschmoll@google.com>
Commit-Queue: Ben Konyi <bkonyi@google.com>

Author: bkonyi

runtime/observatory/tests/service/get_vm_timeline_rpc_test.dart

@@ -127,8 +127,10 @@ var tests = <VMTest>[
         eventsContains(dartEvents, 'i', 'ISYNC', {'fruit': 'banana'}), isTrue);
     expect(eventsContains(dartEvents, 'X', 'apple'), isTrue);
     expect(
-        eventsContains(dartEvents, 'b', 'TASK1',
-            {'task1-start-key': 'task1-start-value', 'parentId': 42}),
+        eventsContains(dartEvents, 'b', 'TASK1', {
+          'task1-start-key': 'task1-start-value',
+          'parentId': 42.toRadixString(16)
+        }),
         isTrue);
     expect(
         eventsContains(dartEvents, 'e', 'TASK1',

sdk/lib/developer/timeline.dart

@@ -209,7 +209,7 @@ class TimelineTask {
     _stack.add(block);
     block._start({
       if (arguments != null) ...arguments,
-      if (_parent != null) 'parentId': _parent._taskId,
+      if (_parent != null) 'parentId': _parent._taskId.toRadixString(16),
     });
   }
 

sdk_nnbd/lib/developer/timeline.dart

@@ -211,7 +211,7 @@ class TimelineTask {
     _stack.add(block);
     block._start({
       if (arguments != null) ...arguments,
-      if (_parent != null) 'parentId': _parent._taskId,
+      if (_parent != null) 'parentId': _parent._taskId.toRadixString(16),
     });
   }