tracing: split trace event filter classes out of TraceLog

base/trace_event/trace_event_filter_test_utils.h

Index: base/trace_event/trace_event_filter_test_utils.h
diff --git a/base/trace_event/trace_event_filter_test_utils.h b/base/trace_event/trace_event_filter_test_utils.h
new file mode 100644
index 0000000000000000000000000000000000000000..419068b221ace663d1e26ba80a074c1026c27f23
--- /dev/null
+++ b/base/trace_event/trace_event_filter_test_utils.h
@@ -0,0 +1,53 @@
+// 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.
+
+#ifndef BASE_TRACE_EVENT_TRACE_EVENT_FILTER_TEST_UTILS_H_

[oystein (OOO til 10th of July), 2016/12/08 20:40:20]

If it's worth splitting this out of the main unit test class, maybe it'd be
better to just take all of the filter events and merge it it all into one
trace_event_filter_test.h/.cc pair (and include the whitelist test there)?

[Primiano Tucci (use gerrit), 2016/12/09 11:50:09]

So, the reason why I split this class out is because in the next CL
(https://codereview.chromium.org/2557743002/) I'm reusing this in another
unittest (event_filter_registry_unittest.cc).

I took a look to the existing trace_event_unittest.cc, but there is too much
shared harness (EndTraceAndFlush(), trace read-back logic etc) which would be a
pity to duplicate.

+#define BASE_TRACE_EVENT_TRACE_EVENT_FILTER_TEST_UTILS_H_
+
+#include <memory>
+#include <string>
+
+#include "base/macros.h"
+#include "base/trace_event/trace_event_filter.h"
+
+namespace base {
+namespace trace_event {
+
+class TestEventFilter : public TraceEventFilter {
+ public:
+  struct HitsCounter {
+    HitsCounter();
+    ~HitsCounter();
+    void Reset();
+    size_t filter_trace_event_hit_count;
+    size_t end_event_hit_count;
+  };
+
+  static const char kName[];
+
+  // Factory method for TraceLog::SetFilterFactoryForTesting().
+  static std::unique_ptr<TraceEventFilter> Factory(
+      const std::string& predicate_name);
+
+  TestEventFilter();
+  ~TestEventFilter() override;
+
+  // TraceEventFilter implementation.
+  bool FilterTraceEvent(const TraceEvent& trace_event) const override;
+  void EndEvent(const char* category_name, const char* name) const override;
+
+  static void set_filter_return_value(bool value) {
+    filter_return_value_ = value;
+  }
+
+ private:
+  static bool filter_return_value_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestEventFilter);
+};
+
+}  // namespace trace_event
+}  // namespace base
+
+#endif  // BASE_TRACE_EVENT_TRACE_EVENT_FILTER_TEST_UTILS_H_