tracing: split trace event filter classes out of TraceLog

base/trace_event/event_name_filter.cc

Index: base/trace_event/event_name_filter.cc
diff --git a/base/trace_event/event_name_filter.cc b/base/trace_event/event_name_filter.cc
new file mode 100644
index 0000000000000000000000000000000000000000..8d0058c147453d9cc9d5f6ff4d48990c114f5bc5
--- /dev/null
+++ b/base/trace_event/event_name_filter.cc
@@ -0,0 +1,26 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/trace_event/event_name_filter.h"
+
+#include "base/trace_event/trace_event_impl.h"
+
+namespace base {
+namespace trace_event {
+
+// static
+const char EventNameFilter::kName[] = "event_whitelist_predicate";
+
+EventNameFilter::EventNameFilter(
+    std::unique_ptr<EventNamesWhitelist> event_names_whitelist)
+    : event_names_whitelist_(std::move(event_names_whitelist)) {}
+
+EventNameFilter::~EventNameFilter() {}
+
+bool EventNameFilter::FilterTraceEvent(const TraceEvent& trace_event) const {
+  return event_names_whitelist_->count(trace_event.name()) != 0;
+}
+
+}  // namespace trace_event
+}  // namespace base