Initial patch for the web modules layered platform proposal.

Source/core/core.gypi

 {
     'includes': [
         'core_generated.gypi',
     ],
     'variables': {
+        'core_web_modules_idl_files': [
+            'dom/Node.idl',

[haraken, 2016/07/30 15:35:02]

It's a bit unfortunate that we need to list up IDL files that have
[WebModulesExposed]. Can we generate the list automatically? (You don't need to
address in this CL though.)

+        ],
         # Files for which bindings (.cpp and .h files) will be generated
         'core_idl_files': [
             'animation/KeyframeEffect.idl',
             'animation/EffectModel.idl',
             'animation/AnimationEffectReadOnly.idl',
             'animation/AnimationEffectTiming.idl',
             'animation/Animation.idl',
             'animation/AnimationTimeline.idl',
             'clipboard/DataTransfer.idl',
             'clipboard/DataTransferItemList.idl',
@@ skipping 3794 matching lines @@
             'style/OutlineValueTest.cpp',
             'style/SVGComputedStyleTest.cpp',
             'svg/UnsafeSVGAttributeSanitizationTest.cpp',
             'testing/PrivateScriptTestTest.cpp',
             'timing/MemoryInfoTest.cpp',
             'workers/WorkerThreadTest.cpp',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }