Test virtual interface [NOT FOR REVIEW]

components/tracing/test/tracing_interface_simulator.h

Index: components/tracing/test/tracing_interface_simulator.h
diff --git a/components/tracing/test/tracing_interface_simulator.h b/components/tracing/test/tracing_interface_simulator.h
new file mode 100644
index 0000000000000000000000000000000000000000..29f13836779485d440ec7a112f673783b227286f
--- /dev/null
+++ b/components/tracing/test/tracing_interface_simulator.h
@@ -0,0 +1,48 @@
+// Copyright 2017 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 COMPONENTS_TRACING_TEST_TRACING_INTERFACE_SIMULATOR_H_
+#define COMPONENTS_TRACING_TEST_TRACING_INTERFACE_SIMULATOR_H_
+
+namespace tracing {
+
+class TracingInterface {
+ public:
+  virtual void AddEvent(const char *category, char type,
+                        const char *name, bool copy_name) const = 0;
+  virtual const bool* GetPointerForCategory(const char *category) const = 0;
+};
+
+void InitTracingInterface();
+const TracingInterface* GetTracingInterface();
+
+void AddEventDirect(const char *category, char type,
+                    const char *name, bool copy_name);
+const bool* GetPointerForCategoryDirect(const char *category);
+
+
+#define TRACE_EVENT_VIRTUAL_TEST(category, name) \
+  TRACE_EVENT_VIRTUAL_TEST_BODY(category, name, cat_enabled_ptr_ ## __LINE__)
+
+#define TRACE_EVENT_VIRTUAL_TEST_BODY(category, name, enabled_ptr) \
+  static const bool* enabled_ptr = nullptr; \

[Primiano Tucci (use gerrit), 2017/01/27 21:26:10]

see comments below

+  if (!enabled_ptr) \
+    enabled_ptr = GetTracingInterface()->GetPointerForCategory(category); \
+  if (*enabled_ptr) \
+    GetTracingInterface()->AddEvent(category, 'X', name, false);
+
+
+#define TRACE_EVENT_DIRECT_TEST(category, name) \
+  TRACE_EVENT_DIRECT_TEST_BODY(category, name, cat_enabled_ptr_ ## __LINE__)
+
+#define TRACE_EVENT_DIRECT_TEST_BODY(category, name, enabled_ptr) \
+  static const bool* enabled_ptr = nullptr; \

[Primiano Tucci (use gerrit), 2017/01/27 21:26:10]

see INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO here. it uses the right set of atomic
ops

+  if (!enabled_ptr) \

[Primiano Tucci (use gerrit), 2017/01/27 21:26:10]

ditto. see INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED, it uses atomic ops

+    enabled_ptr = GetPointerForCategoryDirect(category); \
+  if (*enabled_ptr) \
+    AddEventDirect(category, 'X', name, false);
+
+}  // namespace tracing
+
+#endif  // COMPONENTS_TRACING_TEST_TRACING_INTERFACE_SIMULATOR_H_