Move blob-related code to platform/blob

Source/web/web.gypi

 {
   'variables': {
     'web_files': [
       'ApplicationCacheHost.cpp',
       'ApplicationCacheHostInternal.h',
       'AssertMatchingEnums.cpp',
       'AssociatedURLLoader.cpp',
       'AssociatedURLLoader.h',
       'AutofillPopupMenuClient.cpp',
       'AutofillPopupMenuClient.h',
@@ skipping 94 matching lines @@
       'UserMediaClientImpl.cpp',
       'UserMediaClientImpl.h',
       'ValidationMessageClientImpl.cpp',
       'ValidationMessageClientImpl.h',
       'ViewportAnchor.cpp',
       'ViewportAnchor.h',
       'WebAXObject.cpp',
       'WebArrayBufferView.cpp',
       'WebBindings.cpp',
       'WebBlob.cpp',
-      'WebBlobData.cpp',
       'WebCache.cpp',
       'WebCachedURLRequest.cpp',
       'WebColorName.cpp',
       'WebCrossOriginPreflightResultCache.cpp',
       'WebCustomElement.cpp',
       'WebDOMActivityLogger.cpp',
       'WebDOMCustomEvent.cpp',
       'WebDOMEvent.cpp',
       'WebDOMEventListener.cpp',
       'WebDOMEventListenerPrivate.cpp',
@@ skipping 231 matching lines @@
       ['toolkit_uses_gtk == 1',
         {
           'web_unittest_files': [
             'tests/WebInputEventFactoryTestGtk.cpp',
           ],
         }
       ],
     ],
   },
 }