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

device/media_transfer_protocol/media_transfer_protocol_manager.cc

Index: device/media_transfer_protocol/media_transfer_protocol_manager.cc
diff --git a/device/media_transfer_protocol/media_transfer_protocol_manager.cc b/device/media_transfer_protocol/media_transfer_protocol_manager.cc
index bbd13b3ed45b55fe8404446794c5eb52fd36b7d9..d3fce038001d84765c02f626ebcbe58159eeb571 100644
--- a/device/media_transfer_protocol/media_transfer_protocol_manager.cc
+++ b/device/media_transfer_protocol/media_transfer_protocol_manager.cc
@@ -111,7 +111,7 @@ class MediaTransferProtocolManagerImpl : public MediaTransferProtocolManager {
                            const OpenStorageCallback& callback) OVERRIDE {
     DCHECK(thread_checker_.CalledOnValidThread());
     if (!ContainsKey(storage_info_map_, storage_name)) {
-      callback.Run("", true);
+      callback.Run(std::string(), true);
       return;
     }
     open_storage_callbacks_.push(callback);
@@ -333,13 +333,13 @@ class MediaTransferProtocolManagerImpl : public MediaTransferProtocolManager {
       open_storage_callbacks_.front().Run(handle, false);
     } else {
       NOTREACHED();
-      open_storage_callbacks_.front().Run("", true);
+      open_storage_callbacks_.front().Run(std::string(), true);
     }
     open_storage_callbacks_.pop();
   }
 
   void OnOpenStorageError() {
-    open_storage_callbacks_.front().Run("", true);
+    open_storage_callbacks_.front().Run(std::string(), true);
     open_storage_callbacks_.pop();
   }