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

chrome/common/metrics/entropy_provider_unittest.cc

Index: chrome/common/metrics/entropy_provider_unittest.cc
diff --git a/chrome/common/metrics/entropy_provider_unittest.cc b/chrome/common/metrics/entropy_provider_unittest.cc
index 9881d7ef7c91e614dde1ff06761a2fda916925db..c3547ab7cade8676b270a9b816e40e2f93531111 100644
--- a/chrome/common/metrics/entropy_provider_unittest.cc
+++ b/chrome/common/metrics/entropy_provider_unittest.cc
@@ -200,7 +200,7 @@ TEST_F(EntropyProviderTest, UseOneTimeRandomizationSHA1) {
     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
@@ -228,7 +228,7 @@ TEST_F(EntropyProviderTest, UseOneTimeRandomizationPermuted) {
     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