[Thread-safe] Take deep copy of String/KURL in FormData::deepCopy()

Source/platform/network/FormData.cpp

Index: Source/platform/network/FormData.cpp
diff --git a/Source/platform/network/FormData.cpp b/Source/platform/network/FormData.cpp
index e38093af1f1291d1a25d64ebcf8b7a339cd408fb..4641f730cad98155eaad3a41278c82cfd26bef15 100644
--- a/Source/platform/network/FormData.cpp
+++ b/Source/platform/network/FormData.cpp
@@ -95,13 +95,13 @@ PassRefPtr<FormData> FormData::deepCopy() const
             formData->m_elements.uncheckedAppend(FormDataElement(e.m_data));
             break;
         case FormDataElement::encodedFile:
-            formData->m_elements.uncheckedAppend(FormDataElement(e.m_filename, e.m_fileStart, e.m_fileLength, e.m_expectedFileModificationTime));
+            formData->m_elements.uncheckedAppend(FormDataElement(e.m_filename.isolatedCopy(), e.m_fileStart, e.m_fileLength, e.m_expectedFileModificationTime));
             break;
         case FormDataElement::encodedBlob:
-            formData->m_elements.uncheckedAppend(FormDataElement(e.m_blobUUID, e.m_optionalBlobDataHandle));
+            formData->m_elements.uncheckedAppend(FormDataElement(e.m_blobUUID.isolatedCopy(), e.m_optionalBlobDataHandle));
             break;
         case FormDataElement::encodedFileSystemURL:
-            formData->m_elements.uncheckedAppend(FormDataElement(e.m_fileSystemURL, e.m_fileStart, e.m_fileLength, e.m_expectedFileModificationTime));
+            formData->m_elements.uncheckedAppend(FormDataElement(e.m_fileSystemURL.copy(), e.m_fileStart, e.m_fileLength, e.m_expectedFileModificationTime));
             break;
         }
     }