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

chrome/common/extensions/extension_set_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/files/file_path.h"
 #include "base/logging.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/values.h"
 #include "chrome/common/extensions/extension.h"
@@ skipping 41 matching lines @@
   scoped_refptr<Extension> ext1(CreateTestExtension(
       "a", "https://chrome.google.com/launch", "https://chrome.google.com/"));
 
   scoped_refptr<Extension> ext2(CreateTestExtension(
       "a", "http://code.google.com/p/chromium",
       "http://code.google.com/p/chromium/"));
 
   scoped_refptr<Extension> ext3(CreateTestExtension(
       "b", "http://dev.chromium.org/", "http://dev.chromium.org/"));
 
-  scoped_refptr<Extension> ext4(CreateTestExtension("c", "", ""));
+  scoped_refptr<Extension> ext4(
+      CreateTestExtension("c", std::string(), std::string()));
 
   ASSERT_TRUE(ext1 && ext2 && ext3 && ext4);
 
   ExtensionSet extensions;
 
   // Add an extension.
   extensions.Insert(ext1);
   EXPECT_EQ(1u, extensions.size());
   EXPECT_EQ(ext1, extensions.GetByID(ext1->id()));
 
@@ skipping 38 matching lines @@
   EXPECT_TRUE(extensions.InSameExtent(
       GURL("http://www.google.com/"),
       GURL("http://blog.chromium.org/")));
 
   // Remove one of the extensions.
   extensions.Remove(ext2->id());
   EXPECT_EQ(2u, extensions.size());
   EXPECT_FALSE(extensions.GetByID(ext2->id()));
 
   // Make a union of a set with 3 more extensions (only 2 are new).
-  scoped_refptr<Extension> ext5(CreateTestExtension("d", "", ""));
-  scoped_refptr<Extension> ext6(CreateTestExtension("e", "", ""));
+  scoped_refptr<Extension> ext5(
+      CreateTestExtension("d", std::string(), std::string()));
+  scoped_refptr<Extension> ext6(
+      CreateTestExtension("e", std::string(), std::string()));
   ASSERT_TRUE(ext5 && ext6);
 
   scoped_ptr<ExtensionSet> to_add(new ExtensionSet());
   to_add->Insert(ext3);  // Already in |extensions|, should not affect size.
   to_add->Insert(ext5);
   to_add->Insert(ext6);
 
   ASSERT_TRUE(extensions.Contains(ext3->id()));
   ASSERT_TRUE(extensions.InsertAll(*to_add));
   EXPECT_EQ(4u, extensions.size());
 
   ASSERT_FALSE(extensions.InsertAll(*to_add));  // Re-adding same set no-ops.
   EXPECT_EQ(4u, extensions.size());
 }