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

chrome/common/extensions/api/extension_action/browser_action_manifest_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 "chrome/common/extensions/api/extension_action/action_info.h"
 #include "chrome/common/extensions/api/extension_action/browser_action_handler.h"
 #include "chrome/common/extensions/extension_builder.h"
 #include "chrome/common/extensions/extension_icon_set.h"
 #include "chrome/common/extensions/extension_manifest_constants.h"
 #include "chrome/common/extensions/manifest_tests/extension_manifest_test.h"
@@ skipping 82 matching lines @@
 
   // 24px icon should be ignored.
   EXPECT_EQ(2u, icons.map().size());
   EXPECT_EQ("icon19.png", icons.Get(19, ExtensionIconSet::MATCH_EXACTLY));
   EXPECT_EQ("icon38.png", icons.Get(38, ExtensionIconSet::MATCH_EXACTLY));
 }
 
 TEST_F(BrowserActionManifestTest,
        BrowserActionManifestIcons_InvalidDefaultIcon) {
   scoped_ptr<DictionaryValue> manifest_value = DictionaryBuilder()
-      .Set("name", "Invalid default icon")
-      .Set("version", "1.0.0")
+      .Set("name", "Invalid default icon").Set("version", "1.0.0")
       .Set("manifest_version", 2)
-      .Set("browser_action", DictionaryBuilder()
-          .Set("default_icon", DictionaryBuilder()
-              .Set("19", "")  // Invalid value.
-              .Set("24", "icon24.png")
-              .Set("38", "icon38.png")))
-     .Build();
+      .Set("browser_action",
+           DictionaryBuilder().Set(
+               "default_icon",
+               DictionaryBuilder().Set("19", std::string())  // Invalid value.
+                   .Set("24", "icon24.png").Set("38", "icon38.png"))).Build();
 
   string16 error = ErrorUtils::FormatErrorMessageUTF16(
       errors::kInvalidIconPath, "19");
   LoadAndExpectError(Manifest(manifest_value.get(), "Invalid default icon"),
                      errors::kInvalidIconPath);
 }
 
 }  // namespace
 }  // namespace extensions