Rename ExceptionCode constants to use the names in the spec (2/3)

Source/core/fileapi/FileReader.cpp

Index: Source/core/fileapi/FileReader.cpp
diff --git a/Source/core/fileapi/FileReader.cpp b/Source/core/fileapi/FileReader.cpp
index bf2984177fe5b692aa6880c3082f110c8e9ed25e..308777e7a0f14a3e3e8f3876d3c21b6a78fefad1 100644
--- a/Source/core/fileapi/FileReader.cpp
+++ b/Source/core/fileapi/FileReader.cpp
@@ -145,9 +145,9 @@ void FileReader::readAsDataURL(Blob* blob, ExceptionCode& ec)
 
 void FileReader::readInternal(Blob* blob, FileReaderLoader::ReadType type, ExceptionCode& ec)
 {
-    // If multiple concurrent read methods are called on the same FileReader, INVALID_STATE_ERR should be thrown when the state is LOADING.
+    // If multiple concurrent read methods are called on the same FileReader, InvalidStateError should be thrown when the state is LOADING.
     if (m_state == LOADING) {
-        ec = INVALID_STATE_ERR;
+        ec = InvalidStateError;
         return;
     }