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

sync/internal_api/syncapi_server_connection_manager_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 "sync/internal_api/syncapi_server_connection_manager.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/compiler_specific.h"
 #include "base/synchronization/waitable_event.h"
@@ skipping 27 matching lines @@
     return false;
   }
   virtual int GetResponseContentLength() const OVERRIDE {
     return 0;
   }
   virtual const char* GetResponseContent() const OVERRIDE {
     return "";
   }
   virtual const std::string GetResponseHeaderValue(
       const std::string& name) const OVERRIDE {
-    return "";
+    return std::string();
   }
   virtual void Abort() OVERRIDE {
     wait_for_abort_.Signal();
   }
  private:
   base::WaitableEvent wait_for_abort_;
 };
 
 class BlockingHttpPostFactory : public HttpPostProviderFactory {
  public:
@@ skipping 42 matching lines @@
   bool result = server.PostBufferToPath(
       &params, "/testpath", "testauth", &watcher);
 
   EXPECT_FALSE(result);
   EXPECT_EQ(HttpResponse::CONNECTION_UNAVAILABLE,
             params.response.server_status);
   abort_thread.Stop();
 }
 
 }  // namespace syncer