tracing: simplify lifetime of TraceEventFilter(s)

base/trace_event/trace_event_filter.cc

Index: base/trace_event/trace_event_filter.cc
diff --git a/base/trace_event/trace_event_filter.cc b/base/trace_event/trace_event_filter.cc
index 626529586477d1d1d16f7835c80a916e20b311e8..f03d8bae1f5ce97e0ed0caa44d66d6d07e0ec67d 100644
--- a/base/trace_event/trace_event_filter.cc
+++ b/base/trace_event/trace_event_filter.cc
@@ -7,11 +7,20 @@
 namespace base {
 namespace trace_event {
 
-TraceEventFilter::TraceEventFilter() {}
+TraceEventFilter::TraceEventFilter(
+    std::unique_ptr<TraceEventFilter::Config> config)
+    : config_(std::move(config)) {}
 TraceEventFilter::~TraceEventFilter() {}
 
 void TraceEventFilter::EndEvent(const char* category_name,
                                 const char* event_name) const {}
 
+bool TraceEventFilter::IsEnabledForCategory(const char* category_name) const {
+  return config_->IsEnabledForCategory(category_name);
+}
+
+TraceEventFilter::Config::Config() {}
+TraceEventFilter::Config::~Config() {}
+
 }  // namespace trace_event
 }  // namespace base