Update --force-fieldtrial-params comment to be a little more clear.

chrome/common/variations/variations_util_unittest.cc

 // 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.
 
 #include "chrome/common/variations/variations_util.h"
 
 #include <utility>
 
 #include "base/feature_list.h"
 #include "base/macros.h"
@@ skipping 31 matching lines @@
   EXPECT_EQ("/", variations::GetVariationParamValue(kTrialName, "a"));
   EXPECT_EQ(std::string(), variations::GetVariationParamValue(kTrialName, "b"));
   EXPECT_EQ(std::string(), variations::GetVariationParamValue(kTrialName, "x"));
 
   std::map<std::string, std::string> params;
   EXPECT_TRUE(variations::GetVariationParams(kTrialName, &params));
   EXPECT_EQ(1U, params.size());
   EXPECT_EQ("/", params["a"]);
 }
 
+TEST_F(VariationsUtilTest, AssociateParamsFromStringWithSameStudy) {
+  const std::string kTrialName = "AssociateVariationParams";
+  const std::string kVariationsString =
+      "AssociateVariationParams.A:a/10/b/test,AssociateVariationParams.A:a/x";
+  ASSERT_FALSE(AssociateParamsFromString(kVariationsString));
+}
+
 TEST_F(VariationsUtilTest, AssociateParamsFromFieldTrialConfig) {
   const FieldTrialGroupParams array_kFieldTrialConfig_params[] = {{"x", "1"},
                                                                   {"y", "2"}};
 
   const FieldTrialTestingGroup array_kFieldTrialConfig_groups[] = {
       {"TestStudy1", "TestGroup1", array_kFieldTrialConfig_params, 2, NULL, 0,
        NULL, 0},
       {"TestStudy2", "TestGroup2", NULL, 0, NULL, 0, NULL, 0}};
 
   const FieldTrialTestingConfig kConfig = {
@@ skipping 45 matching lines @@
   EXPECT_TRUE(base::FeatureList::IsEnabled(kFeatureB));
   EXPECT_TRUE(base::FieldTrialList::IsTrialActive("TestStudy1"));
 
   EXPECT_FALSE(base::FieldTrialList::IsTrialActive("TestStudy2"));
   EXPECT_FALSE(base::FeatureList::IsEnabled(kFeatureC));
   EXPECT_FALSE(base::FeatureList::IsEnabled(kFeatureD));
   EXPECT_TRUE(base::FieldTrialList::IsTrialActive("TestStudy2"));
 }
 
 }  // namespace chrome_variations