Initial implementation for sharing field trial state (win)

base/metrics/field_trial_unittest.cc

 // Copyright (c) 2012 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.
 
 #include "base/metrics/field_trial.h"
 
 #include <stddef.h>
 
+#include "base/base_switches.h"
 #include "base/build_time.h"
+#include "base/feature_list.h"
 #include "base/macros.h"
+#include "base/memory/ptr_util.h"
 #include "base/message_loop/message_loop.h"
 #include "base/rand_util.h"
 #include "base/run_loop.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/stringprintf.h"
 #include "base/test/gtest_util.h"
+#include "base/test/mock_entropy_provider.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace base {
 
 namespace {
 
 // Default group name used by several tests.
 const char kDefaultGroupName[] = "DefaultGroup";
 
 // Call FieldTrialList::FactoryGetFieldTrial() with a future expiry date.
@@ skipping 1098 matching lines @@
   // Trying to instantiate a one-time randomized field trial before the
   // FieldTrialList is created should crash.
   EXPECT_DEATH_IF_SUPPORTED(
       FieldTrialList::FactoryGetFieldTrial(
           "OneTimeRandomizedTrialWithoutFieldTrialList", 100, kDefaultGroupName,
           base::FieldTrialList::kNoExpirationYear, 1, 1,
           base::FieldTrial::ONE_TIME_RANDOMIZED, NULL),
       "");
 }
 
+TEST(FieldTrialListTest, TestCopyFieldTrialStateToFlags) {
+  base::FieldTrialList field_trial_list(
+      base::MakeUnique<base::MockEntropyProvider>());
+  base::FieldTrialList::CreateFieldTrial("Trial1", "Group1");
+  base::FilePath test_file_path = base::FilePath(FILE_PATH_LITERAL("Program"));
+  base::CommandLine cmd_line = base::CommandLine(test_file_path);
+
+  std::unique_ptr<base::FeatureList> feature_list(new base::FeatureList);
+  feature_list->InitializeFromCommandLine("ShareFieldTrialStateViaSharedMemory",
+                                          "");
+  base::FeatureList::ClearInstanceForTesting();
+  base::FeatureList::SetInstance(std::move(feature_list));
+
+  std::unique_ptr<base::SharedMemory> field_trial_state =
+      base::FieldTrialList::CopyFieldTrialStateToFlags("field-trial-handle",
+                                                       &cmd_line);
+
+#if defined(OS_WIN)
+  std::string field_trial_state_string(
+      static_cast<char*>(field_trial_state.get()->memory()));

[Alexei Svitkine (slow), 2016/10/06 21:39:28]

Nit: Just inline this into the EXPECT_EQ

[lawrencewu, 2016/10/07 15:07:21]

Done.

+
+  EXPECT_EQ("Trial1/Group1/", field_trial_state_string);
+  EXPECT_TRUE(cmd_line.HasSwitch("field-trial-handle"));
+#else
+  EXPECT_TRUE(field_trial_state.get() == nullptr);
+  EXPECT_TRUE(cmd_line.HasSwitch(switches::kForceFieldTrials));
+#endif
+}
+
 }  // namespace base