Implement File constructor.

Source/bindings/bindings.gypi

 {
     'variables': {
         'bindings_dir': ['.'],
         'bindings_files': [
             'v8/ActiveDOMCallback.cpp',
             'v8/ActiveDOMCallback.h',
             'v8/ArrayValue.cpp',
             'v8/ArrayValue.h',
             'v8/BindingSecurity.cpp',
             'v8/BindingSecurity.h',
@@ skipping 134 matching lines @@
             'v8/WorkerScriptDebugServer.h',
             'v8/WrapperTypeInfo.h',
             'v8/custom/V8AlgorithmCustom.cpp',
             'v8/custom/V8ArrayBufferCustom.cpp',
             'v8/custom/V8ArrayBufferCustom.h',
             'v8/custom/V8ArrayBufferViewCustom.cpp',
             'v8/custom/V8ArrayBufferViewCustom.h',
             'v8/custom/V8AudioNodeCustom.cpp',
             'v8/custom/V8BiquadFilterNodeCustom.cpp',
             'v8/custom/V8BlobCustom.cpp',
+            'v8/custom/V8BlobCustomHelpers.cpp',
+            'v8/custom/V8BlobCustomHelpers.h',
             'v8/custom/V8CSSRuleCustom.cpp',
             'v8/custom/V8CSSStyleDeclarationCustom.cpp',
             'v8/custom/V8CSSValueCustom.cpp',
             'v8/custom/V8CanvasRenderingContext2DCustom.cpp',
             'v8/custom/V8CanvasRenderingContextCustom.cpp',
             'v8/custom/V8CryptoCustom.cpp',
             'v8/custom/V8CustomEventCustom.cpp',
             'v8/custom/V8CustomSQLStatementErrorCallback.cpp',
             'v8/custom/V8CustomXPathNSResolver.cpp',
             'v8/custom/V8CustomXPathNSResolver.h',
             'v8/custom/V8DataViewCustom.cpp',
             'v8/custom/V8DataViewCustom.h',
             'v8/custom/V8DedicatedWorkerGlobalScopeCustom.cpp',
             'v8/custom/V8DeviceMotionEventCustom.cpp',
             'v8/custom/V8DeviceOrientationEventCustom.cpp',
             'v8/custom/V8DocumentCustom.cpp',
             'v8/custom/V8EntryCustom.cpp',
             'v8/custom/V8EntrySyncCustom.cpp',
             'v8/custom/V8EventCustom.cpp',
             'v8/custom/V8EventTargetCustom.cpp',
             'v8/custom/V8ErrorEventCustom.cpp',
+            'v8/custom/V8FileCustom.cpp',
             'v8/custom/V8FileReaderCustom.cpp',
             'v8/custom/V8Float32ArrayCustom.h',
             'v8/custom/V8Float64ArrayCustom.h',
             'v8/custom/V8FormDataCustom.cpp',
             'v8/custom/V8GeolocationCustom.cpp',
             'v8/custom/V8HTMLAllCollectionCustom.cpp',
             'v8/custom/V8HTMLCanvasElementCustom.cpp',
             'v8/custom/V8HTMLCollectionCustom.cpp',
             'v8/custom/V8HTMLDocumentCustom.cpp',
             'v8/custom/V8HTMLElementCustom.cpp',
@@ skipping 81 matching lines @@
                     '<(SHARED_INTERMEDIATE_DIR)/blink/bindings/V8DerivedSources15.cpp',
                     '<(SHARED_INTERMEDIATE_DIR)/blink/bindings/V8DerivedSources16.cpp',
                     '<(SHARED_INTERMEDIATE_DIR)/blink/bindings/V8DerivedSources17.cpp',
                     '<(SHARED_INTERMEDIATE_DIR)/blink/bindings/V8DerivedSources18.cpp',
                     '<(SHARED_INTERMEDIATE_DIR)/blink/bindings/V8DerivedSources19.cpp',
                 ],
             }],
         ],
     },
 }