Use the type alias of base::FieldTrialParams in blink

This CL moves the type alias of FieldTrialParams from
field_trial_param_associator.h to field_trial_params.h and use
base::FieldTrialParams in blink.

Bug: 952716
Change-Id: Ia6587a4799a43591ef19cd88cc0c7292bc22c7f8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1605282Reviewed-by: Luke Halliwell <halliwell@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Commit-Queue: Miyoung Shin(OOO till May 17) <myid.shin@igalia.com>
Cr-Commit-Position: refs/heads/master@{#659185}

base/metrics/field_trial_param_associator.h

@@ -12,6 +12,7 @@
 #include "base/base_export.h"
 #include "base/memory/singleton.h"
 #include "base/metrics/field_trial.h"
+#include "base/metrics/field_trial_params.h"
 #include "base/synchronization/lock.h"
 
 namespace base {
@@ -23,9 +24,6 @@ class BASE_EXPORT FieldTrialParamAssociator {
   FieldTrialParamAssociator();
   ~FieldTrialParamAssociator();
 
-  // Key-value mapping type for field trial parameters.
-  typedef std::map<std::string, std::string> FieldTrialParams;
-
   // Retrieve the singleton.
   static FieldTrialParamAssociator* GetInstance();
 

base/metrics/field_trial_params.cc

@@ -11,22 +11,21 @@
 
 namespace base {
 
-bool AssociateFieldTrialParams(
-    const std::string& trial_name,
-    const std::string& group_name,
-    const std::map<std::string, std::string>& params) {
+bool AssociateFieldTrialParams(const std::string& trial_name,
+                               const std::string& group_name,
+                               const FieldTrialParams& params) {
   return base::FieldTrialParamAssociator::GetInstance()
       ->AssociateFieldTrialParams(trial_name, group_name, params);
 }
 
 bool GetFieldTrialParams(const std::string& trial_name,
-                         std::map<std::string, std::string>* params) {
+                         FieldTrialParams* params) {
   return base::FieldTrialParamAssociator::GetInstance()->GetFieldTrialParams(
       trial_name, params);
 }
 
 bool GetFieldTrialParamsByFeature(const base::Feature& feature,
-                                  std::map<std::string, std::string>* params) {
+                                  FieldTrialParams* params) {
   if (!base::FeatureList::IsEnabled(feature))
     return false;
 
@@ -39,7 +38,7 @@ bool GetFieldTrialParamsByFeature(const base::Feature& feature,
 
 std::string GetFieldTrialParamValue(const std::string& trial_name,
                                     const std::string& param_name) {
-  std::map<std::string, std::string> params;
+  FieldTrialParams params;
   if (GetFieldTrialParams(trial_name, &params)) {
     auto it = params.find(param_name);
     if (it != params.end())

base/metrics/field_trial_params.h

@@ -14,14 +14,16 @@ namespace base {
 
 struct Feature;
 
+// Key-value mapping type for field trial parameters.
+typedef std::map<std::string, std::string> FieldTrialParams;
+
 // Associates the specified set of key-value |params| with the field trial
 // specified by |trial_name| and |group_name|. Fails and returns false if the
 // specified field trial already has params associated with it or the trial
 // is already active (group() has been called on it). Thread safe.
-BASE_EXPORT bool AssociateFieldTrialParams(
-    const std::string& trial_name,
-    const std::string& group_name,
-    const std::map<std::string, std::string>& params);
+BASE_EXPORT bool AssociateFieldTrialParams(const std::string& trial_name,
+                                           const std::string& group_name,
+                                           const FieldTrialParams& params);
 
 // Retrieves the set of key-value |params| for the specified field trial, based
 // on its selected group. If the field trial does not exist or its selected
@@ -29,9 +31,8 @@ BASE_EXPORT bool AssociateFieldTrialParams(
 // does not modify |params|. Calling this function will result in the field
 // trial being marked as active if found (i.e. group() will be called on it),
 // if it wasn't already. Thread safe.
-BASE_EXPORT bool GetFieldTrialParams(
-    const std::string& trial_name,
-    std::map<std::string, std::string>* params);
+BASE_EXPORT bool GetFieldTrialParams(const std::string& trial_name,
+                                     FieldTrialParams* params);
 
 // Retrieves the set of key-value |params| for the field trial associated with
 // the specified |feature|. A feature is associated with at most one field
@@ -40,9 +41,8 @@ BASE_EXPORT bool GetFieldTrialParams(
 // returns false and does not modify |params|. Calling this function will
 // result in the associated field trial being marked as active if found (i.e.
 // group() will be called on it), if it wasn't already. Thread safe.
-BASE_EXPORT bool GetFieldTrialParamsByFeature(
-    const base::Feature& feature,
-    std::map<std::string, std::string>* params);
+BASE_EXPORT bool GetFieldTrialParamsByFeature(const base::Feature& feature,
+                                              FieldTrialParams* params);
 
 // Retrieves a specific parameter value corresponding to |param_name| for the
 // specified field trial, based on its selected group. If the field trial does

chromecast/base/cast_features.cc

@@ -251,7 +251,7 @@ void InitializeFeatureList(const base::DictionaryValue& dcs_features,
               feature_name, base::FeatureList::OVERRIDE_DISABLE_FEATURE)) {
         // Build a map of the FieldTrial parameters and associate it to the
         // FieldTrial.
-        base::FieldTrialParamAssociator::FieldTrialParams params;
+        base::FieldTrialParams params;
         for (Iterator p(*params_dict); !p.IsAtEnd(); p.Advance()) {
           std::string val;
           if (p.value().GetAsString(&val)) {

third_party/blink/renderer/platform/loader/fetch/resource_load_scheduler.cc

@@ -80,7 +80,7 @@ base::HistogramBase::Sample ToSample(ReportCircumstance circumstance) {
 uint32_t GetFieldTrialUint32Param(const char* trial_name,
                                   const char* parameter_name,
                                   uint32_t default_param) {
-  std::map<std::string, std::string> trial_params;
+  base::FieldTrialParams trial_params;
   bool result = base::GetFieldTrialParams(trial_name, &trial_params);
   if (!result)
     return default_param;

third_party/blink/renderer/platform/scheduler/main_thread/frame_scheduler_impl_unittest.cc

@@ -1532,9 +1532,9 @@ class ResourceFetchPriorityExperimentTest : public FrameSchedulerImplTest {
  public:
   ResourceFetchPriorityExperimentTest()
       : FrameSchedulerImplTest({kUseResourceFetchPriority}, {}) {
-    std::map<std::string, std::string> params{
-        {"HIGHEST", "HIGH"}, {"MEDIUM", "NORMAL"}, {"LOW", "NORMAL"},
-        {"LOWEST", "LOW"},   {"IDLE", "LOW"},      {"THROTTLED", "LOW"}};
+    base::FieldTrialParams params{{"HIGHEST", "HIGH"}, {"MEDIUM", "NORMAL"},
+                                  {"LOW", "NORMAL"},   {"LOWEST", "LOW"},
+                                  {"IDLE", "LOW"},     {"THROTTLED", "LOW"}};
 
     const char kStudyName[] = "ResourceFetchPriorityExperiment";
     const char kGroupName[] = "GroupName1";
@@ -1567,9 +1567,9 @@ class ResourceFetchPriorityExperimentOnlyWhenLoadingTest
  public:
   ResourceFetchPriorityExperimentOnlyWhenLoadingTest()
       : FrameSchedulerImplTest({kUseResourceFetchPriorityOnlyWhenLoading}, {}) {
-    std::map<std::string, std::string> params{
-        {"HIGHEST", "HIGH"}, {"MEDIUM", "NORMAL"}, {"LOW", "NORMAL"},
-        {"LOWEST", "LOW"},   {"IDLE", "LOW"},      {"THROTTLED", "LOW"}};
+    base::FieldTrialParams params{{"HIGHEST", "HIGH"}, {"MEDIUM", "NORMAL"},
+                                  {"LOW", "NORMAL"},   {"LOWEST", "LOW"},
+                                  {"IDLE", "LOW"},     {"THROTTLED", "LOW"}};
 
     const char kStudyName[] = "ResourceFetchPriorityExperiment";
     const char kGroupName[] = "GroupName2";
@@ -1746,9 +1746,8 @@ TEST_F(FrameSchedulerImplTest, TaskTypeToTaskQueueMapping) {
 
 class ThrottleAndFreezeTaskTypesExperimentTest : public FrameSchedulerImplTest {
  public:
-  ThrottleAndFreezeTaskTypesExperimentTest(
-      std::map<std::string, std::string> params,
-      const char* group_name) {
+  ThrottleAndFreezeTaskTypesExperimentTest(const base::FieldTrialParams& params,
+                                           const char* group_name) {
     const char kStudyName[] = "ThrottleAndFreezeTaskTypes";
 
     field_trial_list_ = std::make_unique<base::FieldTrialList>(nullptr);
@@ -1772,7 +1771,7 @@ class ThrottleableAndFreezableTaskTypesTest
  public:
   ThrottleableAndFreezableTaskTypesTest()
       : ThrottleAndFreezeTaskTypesExperimentTest(
-            std::map<std::string, std::string>{
+            base::FieldTrialParams{
                 // Leading spaces are allowed.
                 {kThrottleableTaskTypesListParam, "PostedMessage"},
                 {kFreezableTaskTypesListParam,
@@ -1826,7 +1825,7 @@ class FreezableOnlyTaskTypesTest
  public:
   FreezableOnlyTaskTypesTest()
       : ThrottleAndFreezeTaskTypesExperimentTest(
-            std::map<std::string, std::string>{
+            base::FieldTrialParams{
                 {kThrottleableTaskTypesListParam, ""},
                 {kFreezableTaskTypesListParam,
                  "PostedMessage,MediaElementEvent,DOMManipulation"}},
@@ -1880,7 +1879,7 @@ class ThrottleableOnlyTaskTypesTest
  public:
   ThrottleableOnlyTaskTypesTest()
       : ThrottleAndFreezeTaskTypesExperimentTest(
-            std::map<std::string, std::string>{
+            base::FieldTrialParams{
                 {kFreezableTaskTypesListParam, ""},
                 {kThrottleableTaskTypesListParam, "PostedMessage"}},
             "Group3") {}

third_party/blink/renderer/platform/scheduler/main_thread/main_thread_scheduler_impl.cc

@@ -565,7 +565,7 @@ MainThreadSchedulerImpl::SchedulingSettings::SchedulingSettings() {
 
   if (use_resource_fetch_priority ||
       use_resource_priorities_only_during_loading) {
-    std::map<std::string, std::string> params;
+    base::FieldTrialParams params;
     base::GetFieldTrialParams(kResourceFetchPriorityExperiment, &params);
     for (size_t net_priority = 0;
          net_priority < net::RequestPrioritySize::NUM_PRIORITIES;

third_party/blink/renderer/platform/scheduler/main_thread/page_scheduler_impl.cc

@@ -68,10 +68,9 @@ struct BackgroundThrottlingSettings {
   base::Optional<base::TimeDelta> initial_budget;
 };
 
-double GetDoubleParameterFromMap(
-    const std::map<std::string, std::string>& settings,
-    const std::string& setting_name,
-    double default_value) {
+double GetDoubleParameterFromMap(const base::FieldTrialParams& settings,
+                                 const std::string& setting_name,
+                                 double default_value) {
   const auto& find_it = settings.find(setting_name);
   if (find_it == settings.end())
     return default_value;
@@ -90,7 +89,7 @@ base::Optional<base::TimeDelta> DoubleToOptionalTime(double value) {
 }
 
 BackgroundThrottlingSettings GetBackgroundThrottlingSettings() {
-  std::map<std::string, std::string> background_throttling_settings;
+  base::FieldTrialParams background_throttling_settings;
   base::GetFieldTrialParams("ExpensiveBackgroundTimerThrottling",
                             &background_throttling_settings);
 

third_party/blink/renderer/platform/scheduler/main_thread/page_scheduler_impl_unittest.cc

@@ -1075,16 +1075,16 @@ void ExpensiveTestTask(scoped_refptr<base::TestMockTimeTaskRunner> task_runner,
 }
 
 void InitializeTrialParams() {
-  std::map<std::string, std::string> params = {{"cpu_budget", "0.01"},
-                                               {"max_budget", "0.0"},
-                                               {"initial_budget", "0.0"},
-                                               {"max_delay", "0.0"}};
+  base::FieldTrialParams params = {{"cpu_budget", "0.01"},
+                                   {"max_budget", "0.0"},
+                                   {"initial_budget", "0.0"},
+                                   {"max_delay", "0.0"}};
   const char kParamName[] = "ExpensiveBackgroundTimerThrottling";
   const char kGroupName[] = "Enabled";
   EXPECT_TRUE(base::AssociateFieldTrialParams(kParamName, kGroupName, params));
   EXPECT_TRUE(base::FieldTrialList::CreateFieldTrial(kParamName, kGroupName));
 
-  std::map<std::string, std::string> actual_params;
+  base::FieldTrialParams actual_params;
   base::GetFieldTrialParams(kParamName, &actual_params);
   EXPECT_EQ(actual_params, params);
 }