tracing: split trace event filter classes out of TraceLog

base/trace_event/trace_event_filter_test_utils.cc

+// 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/trace_event_filter_test_utils.h"
+
+#include "base/logging.h"
+
+namespace base {
+namespace trace_event {
+
+namespace {
+TestEventFilter::HitsCounter* g_hits_counter;
+}  // namespace;
+
+// static
+const char TestEventFilter::kName[] = "testing_predicate";
+bool TestEventFilter::filter_return_value_;
+
+// static
+std::unique_ptr<TraceEventFilter> TestEventFilter::Factory(
+    const std::string& predicate_name) {
+  std::unique_ptr<TraceEventFilter> res;
+  if (predicate_name == kName)
+    res.reset(new TestEventFilter());
+  return res;
+}
+
+TestEventFilter::TestEventFilter() {}
+TestEventFilter::~TestEventFilter() {}
+
+bool TestEventFilter::FilterTraceEvent(const TraceEvent& trace_event) const {
+  if (g_hits_counter)
+    g_hits_counter->filter_trace_event_hit_count++;
+  return filter_return_value_;
+}
+
+void TestEventFilter::EndEvent(const char* category_name,
+                               const char* name) const {
+  if (g_hits_counter)
+    g_hits_counter->end_event_hit_count++;
+}
+
+TestEventFilter::HitsCounter::HitsCounter() {
+  Reset();
+  DCHECK(!g_hits_counter);
+  g_hits_counter = this;
+}
+
+TestEventFilter::HitsCounter::~HitsCounter() {
+  DCHECK(g_hits_counter);
+  g_hits_counter = nullptr;
+}
+
+void TestEventFilter::HitsCounter::Reset() {
+  filter_trace_event_hit_count = 0;
+  end_event_hit_count = 0;
+}
+
+}  // namespace trace_event
+}  // namespace base