Control TaskScheduler initialization params in renderers via field trial.

components/task_scheduler_util/common/variations_util_unittest.cc

Index: components/task_scheduler_util/common/variations_util_unittest.cc
diff --git a/components/task_scheduler_util/common/variations_util_unittest.cc b/components/task_scheduler_util/common/variations_util_unittest.cc
index 386d0b0163c0b015ab572786c6db4299302f3985..efdad2f029287aeec775f66e4e5edf9dcfe43727 100644
--- a/components/task_scheduler_util/common/variations_util_unittest.cc
+++ b/components/task_scheduler_util/common/variations_util_unittest.cc
@@ -8,8 +8,13 @@
 #include <string>
 #include <vector>
 
+#include "build/build_config.h"
+#include "base/command_line.h"
+#include "base/macros.h"
+#include "base/metrics/field_trial.h"
 #include "base/task_scheduler/scheduler_worker_pool_params.h"
 #include "base/threading/platform_thread.h"
+#include "components/variations/variations_associated_data.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace task_scheduler_util {
@@ -20,6 +25,13 @@ using StandbyThreadPolicy =
     base::SchedulerWorkerPoolParams::StandbyThreadPolicy;
 using ThreadPriority = base::ThreadPriority;
 
+#if !defined(OS_IOS)
+constexpr char kFieldTrialName[] = "BrowserScheduler";
+constexpr char kFieldTrialTestGroup[] = "Test";
+constexpr char kTaskSchedulerVariationParamsSwitch[] =
+    "task-scheduler-variation-params";
+#endif  // !defined(OS_IOS)
+
 std::vector<SchedulerImmutableWorkerPoolParams> GetImmutableWorkerPoolParams() {
   std::vector<SchedulerImmutableWorkerPoolParams> constant_worker_pool_params;
   constant_worker_pool_params.emplace_back("Background",
@@ -33,9 +45,25 @@ std::vector<SchedulerImmutableWorkerPoolParams> GetImmutableWorkerPoolParams() {
   return constant_worker_pool_params;
 }
 
+class TaskSchedulerUtilVariationsUtilTest : public testing::Test {
+ public:
+  TaskSchedulerUtilVariationsUtilTest() : field_trial_list_(nullptr) {}
+  ~TaskSchedulerUtilVariationsUtilTest() override {
+    // Ensure that the maps are cleared between tests, since they are stored as
+    // process singletons.
+    variations::testing::ClearAllVariationIDs();
+    variations::testing::ClearAllVariationParams();
+  }
+
+ private:
+  base::FieldTrialList field_trial_list_;
+
+  DISALLOW_COPY_AND_ASSIGN(TaskSchedulerUtilVariationsUtilTest);
+};
+
 }  // namespace
 
-TEST(TaskSchedulerUtilVariationsUtilTest, OrderingParams5) {
+TEST_F(TaskSchedulerUtilVariationsUtilTest, OrderingParams5) {
   std::map<std::string, std::string> variation_params;
   variation_params["Background"] = "1;1;1;0;42";
   variation_params["BackgroundFileIO"] = "2;2;1;0;52";
@@ -75,7 +103,7 @@ TEST(TaskSchedulerUtilVariationsUtilTest, OrderingParams5) {
             params_vector[3].suggested_reclaim_time());
 }
 
-TEST(TaskSchedulerUtilVariationsUtilTest, OrderingParams6) {
+TEST_F(TaskSchedulerUtilVariationsUtilTest, OrderingParams6) {
   std::map<std::string, std::string> variation_params;
   variation_params["Background"] = "1;1;1;0;42;lazy";
   variation_params["BackgroundFileIO"] = "2;2;1;0;52;one";
@@ -117,13 +145,13 @@ TEST(TaskSchedulerUtilVariationsUtilTest, OrderingParams6) {
             params_vector[3].suggested_reclaim_time());
 }
 
-TEST(TaskSchedulerUtilVariationsUtilTest, NoData) {
+TEST_F(TaskSchedulerUtilVariationsUtilTest, NoData) {
   EXPECT_TRUE(GetWorkerPoolParams(GetImmutableWorkerPoolParams(),
                                   std::map<std::string, std::string>())
                   .empty());
 }
 
-TEST(TaskSchedulerUtilVariationsUtilTest, IncompleteParameters) {
+TEST_F(TaskSchedulerUtilVariationsUtilTest, IncompleteParameters) {
   std::map<std::string, std::string> variation_params;
   variation_params["Background"] = "1;1;1;0";
   variation_params["BackgroundFileIO"] = "2;2;1;0";
@@ -134,7 +162,7 @@ TEST(TaskSchedulerUtilVariationsUtilTest, IncompleteParameters) {
           .empty());
 }
 
-TEST(TaskSchedulerUtilVariationsUtilTest, InvalidParameters) {
+TEST_F(TaskSchedulerUtilVariationsUtilTest, InvalidParameters) {
   std::map<std::string, std::string> variation_params;
   variation_params["Background"] = "a;b;c;d;e";
   variation_params["BackgroundFileIO"] = "a;b;c;d;e";
@@ -145,4 +173,76 @@ TEST(TaskSchedulerUtilVariationsUtilTest, InvalidParameters) {
           .empty());
 }
 
+#if !defined(OS_IOS)
+// Verify that AddVariationParamsToCommandLine() serializes BrowserScheduler
+// variation params that start with the specified prefix to the command line and
+// that GetVariationParamsFromCommandLine() correctly deserializes them.
+TEST_F(TaskSchedulerUtilVariationsUtilTest, CommandLine) {
+  std::map<std::string, std::string> in_variation_params;
+  in_variation_params["PrefixFoo"] = "Foo";
+  in_variation_params["PrefixBar"] = "Bar";
+  in_variation_params["NoPrefix"] = "NoPrefix";
+  ASSERT_TRUE(variations::AssociateVariationParams(
+      kFieldTrialName, kFieldTrialTestGroup, in_variation_params));
+  base::FieldTrialList::CreateFieldTrial(kFieldTrialName, kFieldTrialTestGroup);
+
+  base::CommandLine command_line(base::CommandLine::NO_PROGRAM);
+  AddVariationParamsToCommandLine("Prefix", &command_line);
+  const std::map<std::string, std::string> out_variation_params =
+      GetVariationParamsFromCommandLine(command_line);
+
+  std::map<std::string, std::string> expected_out_variation_params;
+  expected_out_variation_params["PrefixFoo"] = "Foo";
+  expected_out_variation_params["PrefixBar"] = "Bar";
+  EXPECT_EQ(expected_out_variation_params, out_variation_params);
+}
+
+// Verify that AddVariationParamsToCommandLine() doesn't add anything to the
+// command line when a BrowserScheduler variation param key contains |. A key
+// that contains | wouldn't be deserialized correctly by
+// GetVariationParamsFromCommandLine().
+TEST_F(TaskSchedulerUtilVariationsUtilTest,
+       CommandLineSeparatorInVariationParamsKey) {
+  std::map<std::string, std::string> in_variation_params;
+  in_variation_params["PrefixFoo"] = "Foo";
+  in_variation_params["PrefixKey|"] = "Value";
+  ASSERT_TRUE(variations::AssociateVariationParams(
+      kFieldTrialName, kFieldTrialTestGroup, in_variation_params));
+  base::FieldTrialList::CreateFieldTrial(kFieldTrialName, kFieldTrialTestGroup);
+
+  base::CommandLine command_line(base::CommandLine::NO_PROGRAM);
+  AddVariationParamsToCommandLine("Prefix", &command_line);
+  EXPECT_TRUE(
+      command_line.GetSwitchValueASCII(kTaskSchedulerVariationParamsSwitch)
+          .empty());
+}
+
+// Verify that AddVariationParamsToCommandLine() doesn't add anything to the
+// command line when a BrowserScheduler variation param value contains |. A
+// value that contains | wouldn't be deserialized correctly by
+// GetVariationParamsFromCommandLine().
+TEST_F(TaskSchedulerUtilVariationsUtilTest,
+       CommandLineSeparatorInVariationParamsValue) {
+  std::map<std::string, std::string> in_variation_params;
+  in_variation_params["PrefixFoo"] = "Foo";
+  in_variation_params["PrefixKey"] = "Value|";
+  ASSERT_TRUE(variations::AssociateVariationParams(
+      kFieldTrialName, kFieldTrialTestGroup, in_variation_params));
+  base::FieldTrialList::CreateFieldTrial(kFieldTrialName, kFieldTrialTestGroup);
+
+  base::CommandLine command_line(base::CommandLine::NO_PROGRAM);
+  AddVariationParamsToCommandLine("Prefix", &command_line);
+  EXPECT_TRUE(
+      command_line.GetSwitchValueASCII(kTaskSchedulerVariationParamsSwitch)
+          .empty());
+}
+
+// Verify that GetVariationParamsFromCommandLine() returns an empty map when the
+// command line doesn't have a --task-scheduler-variation-params switch.
+TEST_F(TaskSchedulerUtilVariationsUtilTest, CommandLineNoSwitch) {
+  base::CommandLine command_line(base::CommandLine::NO_PROGRAM);
+  EXPECT_TRUE(GetVariationParamsFromCommandLine(command_line).empty());
+}
+#endif  // !defined(OS_IOS)
+
 }  // namespace task_scheduler_util