Control TaskScheduler initialization params in renderers via field trial.

components/task_scheduler_util/common/variations_util.h

 // 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 COMPONENTS_TASK_SCHEDULER_UTIL_COMMON_VARIATIONS_UTIL_H_
 #define COMPONENTS_TASK_SCHEDULER_UTIL_COMMON_VARIATIONS_UTIL_H_
 
 #include <map>
 #include <string>
 #include <vector>
 
+#include "base/strings/string_piece.h"
 #include "base/task_scheduler/scheduler_worker_pool_params.h"
 #include "base/threading/platform_thread.h"
 
+namespace base {
+class CommandLine;
+}
+
 namespace task_scheduler_util {
 
 struct SchedulerImmutableWorkerPoolParams {
   SchedulerImmutableWorkerPoolParams(const char* name_in,
                                      base::ThreadPriority priority_hint_in);
 
   const char* const name;
   const base::ThreadPriority priority_hint;
 };
 
 // Returns a SchedulerWorkerPoolParams vector to initialize pools specified in
 // |constant_worker_pool_params_vector|. SchedulerWorkerPoolParams members
 // without a counterpart in SchedulerImmutableWorkerPoolParams are initialized
 // based of |variation_params|. Returns an empty vector on failure.
 std::vector<base::SchedulerWorkerPoolParams> GetWorkerPoolParams(
     const std::vector<SchedulerImmutableWorkerPoolParams>
         constant_worker_pool_params_vector,
     const std::map<std::string, std::string>& variation_params);
 
+// Adds key-value pairs from |variation_params| whose key start with

[robliao, 2017/01/03 08:00:01]

Nit: Serializes key-value pairs from |variations_params| from keys starting with
|key_prefix| ...

[fdoray, 2017/01/04 22:47:38]

Done.

+// |key_prefix| to the --task-scheduler-variation-params switch of
+// |command_line|.
+void AddVariationParamsToCommandLine(
+    const std::map<std::string, std::string> variation_params,
+    base::StringPiece key_prefix,
+    base::CommandLine* command_line);
+
+// Returns a map with key-value pairs read from the

[robliao, 2017/01/03 08:00:01]

Nit: Returns a map of key-value pairs deserialized from the...

[fdoray, 2017/01/04 22:47:38]

Done.

+// --task-scheduler-variation-params switch of |command_line|.
+std::map<std::string, std::string> GetVariationParamsFromCommandLine(
+    const base::CommandLine& command_line);
+
 }  // namespace task_scheduler_util
 
 #endif  // COMPONENTS_TASK_SCHEDULER_UTIL_COMMON_VARIATIONS_UTIL_H_