Set up background memory light tracing field trials

content/browser/tracing/background_tracing_config_impl.h

 // 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_BROWSER_TRACING_BACKGROUND_TRACING_CONFIG_IMPL_H_
 #define CONTENT_BROWSER_TRACING_BACKGROUND_TRACING_CONFIG_IMPL_H_
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/scoped_vector.h"
@@ skipping 15 matching lines @@
 
   enum CategoryPreset {
     CATEGORY_PRESET_UNSET,
     BENCHMARK,
     BENCHMARK_DEEP,
     BENCHMARK_GPU,
     BENCHMARK_IPC,
     BENCHMARK_STARTUP,
     BENCHMARK_BLINK_GC,
     BENCHMARK_MEMORY_HEAVY,
+    BENCHMARK_MEMORY_LIGHT,
     BENCHMARK_EXECUTION_METRIC,
     BLINK_STYLE
   };
 
   CategoryPreset category_preset() const { return category_preset_; }
   void set_category_preset(CategoryPreset category_preset) {
     category_preset_ = category_preset;
   }
 
   const ScopedVector<BackgroundTracingRule>& rules() const { return rules_; }
@@ skipping 33 matching lines @@
   std::string scenario_name_;
   std::string enable_blink_features_;
   std::string disable_blink_features_;
 
   DISALLOW_COPY_AND_ASSIGN(BackgroundTracingConfigImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_TRACING_BACKGROUND_TRACING_CONFIG_IMPL_H_