Factor File API's 'partial interface URL' impl into separate files

third_party/WebKit/Source/core/core.gypi

 {
     'includes': [
         'core_generated.gypi',
     ],
     'variables': {
         # Files for which bindings (.cpp and .h files) will be generated
         'core_idl_files': [
             'animation/KeyframeEffect.idl',
             'animation/EffectModel.idl',
             'animation/AnimationEffectReadOnly.idl',
@@ skipping 413 matching lines @@
             'dom/DocumentFullscreen.idl',
             'dom/DocumentOrShadowRoot.idl',
             'dom/ElementFullscreen.idl',
             'dom/GlobalEventHandlers.idl',
             'dom/NonDocumentTypeChildNode.idl',
             'dom/NonElementParentNode.idl',
             'dom/ParentNode.idl',
             'dom/URLUtilsReadOnly.idl',
             'events/EventListener.idl',
             'events/NavigatorEvents.idl',
+            'fileapi/URLFileAPI.idl',
             'frame/NavigatorCPU.idl',
             'frame/NavigatorID.idl',
             'frame/NavigatorLanguage.idl',
             'frame/NavigatorOnLine.idl',
             'frame/NavigatorStorageUtils.idl',
             'frame/WindowBase64.idl',
             'frame/WindowEventHandlers.idl',
             'frame/WindowTimers.idl',
             'html/HTMLHyperlinkElementUtils.idl',
             'imagebitmap/ImageBitmapFactories.idl',
@@ skipping 1233 matching lines @@
             'fileapi/FileError.h',
             'fileapi/FileList.cpp',
             'fileapi/FileList.h',
             'fileapi/FileReader.cpp',
             'fileapi/FileReader.h',
             'fileapi/FileReaderLoader.cpp',
             'fileapi/FileReaderLoader.h',
             'fileapi/FileReaderLoaderClient.h',
             'fileapi/FileReaderSync.cpp',
             'fileapi/FileReaderSync.h',
+            'fileapi/URLFileAPI.cpp',
+            'fileapi/URLFileAPI.h',
             'frame/BarProp.cpp',
             'frame/BarProp.h',
             'frame/DOMTimer.cpp',
             'frame/DOMTimer.h',
             'frame/DOMTimerCoordinator.cpp',
             'frame/DOMTimerCoordinator.h',
             'frame/DOMWindow.cpp',
             'frame/DOMWindow.h',
             'frame/DOMWindowBase64.cpp',
             'frame/DOMWindowBase64.h',
@@ skipping 2404 matching lines @@
             'svg/SVGPathParserTest.cpp',
             'svg/UnsafeSVGAttributeSanitizationTest.cpp',
             'testing/PrivateScriptTestTest.cpp',
             'timing/MemoryInfoTest.cpp',
             'workers/WorkerThreadTest.cpp',
             'workers/WorkerThreadTestHelper.h',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }