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

chrome/common/variations/variations_util_unittest.cc

Index: chrome/common/variations/variations_util_unittest.cc
diff --git a/chrome/common/variations/variations_util_unittest.cc b/chrome/common/variations/variations_util_unittest.cc
index 87d58ad5636acab17cf253f42efc3eaaad40e534..21eba93dc9c284e846dd0570bbdf1d25f546aeaa 100644
--- a/chrome/common/variations/variations_util_unittest.cc
+++ b/chrome/common/variations/variations_util_unittest.cc
@@ -49,6 +49,13 @@ TEST_F(VariationsUtilTest, AssociateParamsFromString) {
   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"}};