Inherit EventTarget interface instead of duplicating its code

Source/core/fileapi/FileReader.idl

Index: Source/core/fileapi/FileReader.idl
diff --git a/Source/core/fileapi/FileReader.idl b/Source/core/fileapi/FileReader.idl
index d551b0f76906c3437fe2ba46358c3e98ab0288c8..2727d12b157cd9133bd7f9f447916190f7d4df76 100644
--- a/Source/core/fileapi/FileReader.idl
+++ b/Source/core/fileapi/FileReader.idl
@@ -33,9 +33,8 @@
     GlobalContext=Window&WorkerGlobalScope,
     ActiveDOMObject,
     Constructor,
-    ConstructorCallWith=ScriptExecutionContext,
-    EventTarget
-] interface FileReader {
+    ConstructorCallWith=ScriptExecutionContext
+] interface FileReader : EventTarget {
     // ready states
     const unsigned short EMPTY = 0;
     const unsigned short LOADING = 1;
@@ -55,15 +54,6 @@
 
     readonly attribute FileError error;
 
-    // EventTarget interface
-    void addEventListener(DOMString type,
-                          EventListener listener,
-                          optional boolean useCapture);
-    void removeEventListener(DOMString type,
-                             EventListener listener,
-                             optional boolean useCapture);
-    [RaisesException] boolean dispatchEvent(Event evt);
-
     attribute EventListener onloadstart;
     attribute EventListener onprogress;
     attribute EventListener onload;