Implement Reactive Configuration in Background Tracing

content/public/browser/background_tracing_preemptive_config.h

Index: content/public/browser/background_tracing_preemptive_config.h
diff --git a/content/public/browser/background_tracing_preemptive_config.h b/content/public/browser/background_tracing_preemptive_config.h
new file mode 100644
index 0000000000000000000000000000000000000000..4731f79622c4b2ed3206a0e18a51f57e72608f65
--- /dev/null
+++ b/content/public/browser/background_tracing_preemptive_config.h
@@ -0,0 +1,45 @@
+// Copyright 2015 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 CONTENT_PUBLIC_BROWSER_BACKGROUND_TRACING_PREEMPTIVE_CONFIG_H_
+#define CONTENT_PUBLIC_BROWSER_BACKGROUND_TRACING_PREEMPTIVE_CONFIG_H_
+
+#include "content/public/browser/background_tracing_config.h"
+
+namespace content {
+
+// BackgroundTracingPreemptiveConfig holds trigger rules for use during
+// preemptive tracing. Tracing will be enabled immediately, and whenever
+// a trigger occurs, the trace will be finalized.
+struct CONTENT_EXPORT BackgroundTracingPreemptiveConfig
+    : public BackgroundTracingConfig {
+ public:
+  BackgroundTracingPreemptiveConfig();
+  ~BackgroundTracingPreemptiveConfig() override;
+
+  enum RuleType {
+    MONITOR_AND_DUMP_WHEN_TRIGGER_NAMED,
+    MONITOR_AND_DUMP_WHEN_SPECIFIC_HISTOGRAM_AND_VALUE,
+    MONITOR_AND_DUMP_WHEN_BROWSER_STARTUP_COMPLETE,
+  };
+  struct HistogramTriggerInfo {
+    std::string histogram_name_to_trigger_on;
+    int histogram_bin_to_trigger_on;
+  };
+  struct NamedTriggerInfo {
+    std::string trigger_name;
+  };
+  struct MonitoringRule {
+    RuleType type;
+    HistogramTriggerInfo histogram_trigger_info;
+    NamedTriggerInfo named_trigger_info;
+  };
+
+  std::vector<MonitoringRule> configs;
+  CategoryPreset category_preset;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_BROWSER_BACKGROUND_TRACING_PREEMPTIVE_CONFIG_H_