Rewrite std::string("") to std::string(), Linux edition.

chrome/common/metrics/entropy_provider_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 <cmath>
 #include <limits>
 #include <numeric>
 
 #include "base/basictypes.h"
 #include "base/guid.h"
@@ skipping 182 matching lines @@
   scoped_refptr<base::FieldTrial> trials[] = {
       base::FieldTrialList::FactoryGetFieldTrial("one", 100, "default",
           base::FieldTrialList::kNoExpirationYear, 1, 1, NULL),
       base::FieldTrialList::FactoryGetFieldTrial("two", 100, "default",
           base::FieldTrialList::kNoExpirationYear, 1, 1, NULL) };
 
   for (size_t i = 0; i < arraysize(trials); ++i) {
     trials[i]->UseOneTimeRandomization();
 
     for (int j = 0; j < 100; ++j)
-      trials[i]->AppendGroup("", 1);
+      trials[i]->AppendGroup(std::string(), 1);
   }
 
   // The trials are most likely to give different results since they have
   // different names.
   EXPECT_NE(trials[0]->group(), trials[1]->group());
   EXPECT_NE(trials[0]->group_name(), trials[1]->group_name());
 }
 
 TEST_F(EntropyProviderTest, UseOneTimeRandomizationPermuted) {
   // Simply asserts that two trials using one-time randomization
   // that have different names, normally generate different results.
   //
   // Note that depending on the one-time random initialization, they
   // _might_ actually give the same result, but we know that given
   // the particular client_id we use for unit tests they won't.
   base::FieldTrialList field_trial_list(
       new PermutedEntropyProvider(1234, kMaxLowEntropySize));
   scoped_refptr<base::FieldTrial> trials[] = {
       base::FieldTrialList::FactoryGetFieldTrial("one", 100, "default",
           base::FieldTrialList::kNoExpirationYear, 1, 1, NULL),
       base::FieldTrialList::FactoryGetFieldTrial("two", 100, "default",
           base::FieldTrialList::kNoExpirationYear, 1, 1, NULL) };
 
   for (size_t i = 0; i < arraysize(trials); ++i) {
     trials[i]->UseOneTimeRandomization();
 
     for (int j = 0; j < 100; ++j)
-      trials[i]->AppendGroup("", 1);
+      trials[i]->AppendGroup(std::string(), 1);
   }
 
   // The trials are most likely to give different results since they have
   // different names.
   EXPECT_NE(trials[0]->group(), trials[1]->group());
   EXPECT_NE(trials[0]->group_name(), trials[1]->group_name());
 }
 
 TEST_F(EntropyProviderTest, SHA1Entropy) {
   const double results[] = { GenerateSHA1Entropy("hi", "1"),
@@ skipping 87 matching lines @@
       ++count;
     }
 
     ASSERT_LT(count, kMaxAttempts) << "Expected average was " <<
         kExpectedAverage << ", average ended at " << cumulative_average <<
         ", for trial " << kTestTrialNames[i];
   }
 }
 
 }  // namespace metrics