Bug 1160279: Recreate nsIFiles in the content process for dragged files. r=smaug

--HG--
extra : rebase_source : f90e7cb31486ef8fd29769c86f25f8341b7b97e6
extra : amend_source : ec7283835b92bc45715549420163059e8f45f187

dom/ipc/ContentChild.cpp

@@ -2898,7 +2898,16 @@ ContentChild::RecvInvokeDragSession(nsTArray<IPCDataTransfer>&& aTransfers,
           } else if (item.data().type() == IPCDataTransferData::TPBlobChild) {
             BlobChild* blob = static_cast<BlobChild*>(item.data().get_PBlobChild());
             nsRefPtr<FileImpl> fileImpl = blob->GetBlobImpl();
-            variant->SetAsISupports(fileImpl);
+            nsString path;
+            ErrorResult result;
+            fileImpl->GetMozFullPathInternal(path, result);
+            if (result.Failed()) {
+              variant->SetAsISupports(fileImpl);
+            } else {
+              nsCOMPtr<nsIFile> file;
+              NS_NewNativeLocalFile(NS_ConvertUTF16toUTF8(path), true, getter_AddRefs(file));
+              variant->SetAsISupports(file);
+            }
           } else {
             continue;
           }