Make stack sampling profiler sample beyond startup.

components/metrics/child_call_stack_profile_collector.h

Index: components/metrics/child_call_stack_profile_collector.h
diff --git a/components/metrics/child_call_stack_profile_collector.h b/components/metrics/child_call_stack_profile_collector.h
index 7eb3abae8146517dc7863d49f8c77b9d3fee59ff..e00d486c81547b8042877745c9bf0ad4ddb89067 100644
--- a/components/metrics/child_call_stack_profile_collector.h
+++ b/components/metrics/child_call_stack_profile_collector.h
@@ -90,9 +90,14 @@ class ChildCallStackProfileCollector {
 
   using CallStackProfile = base::StackSamplingProfiler::CallStackProfile;
 
-  void Collect(const CallStackProfileParams& params,
-               base::TimeTicks start_timestamp,
-               std::vector<CallStackProfile> profiles);
+  base::Optional<base::StackSamplingProfiler::SamplingParams> Collect(
+      const CallStackProfileParams& params,
+      base::TimeTicks start_timestamp,
+      std::vector<CallStackProfile> profiles);
+
+  void CollectImpl(const CallStackProfileParams& params,
+                   base::TimeTicks start_timestamp,
+                   std::vector<CallStackProfile> profiles);
 
   // This object may be accessed on any thread, including the profiler
   // thread. The expected use case for the object is to be created and have