Have the form control element directly handle validation message updating.

Source/core/core.gypi

 {
     'includes': [
       'core_generated.gypi',
     ],
     'variables': {
         # Files for which bindings (.cpp and .h files) will be generated
         'core_idl_files': [
             'animation/Animation.idl',
             'animation/AnimationEffect.idl',
             'animation/AnimationPlayer.idl',
@@ skipping 2641 matching lines @@
             'html/forms/TextFieldInputType.cpp',
             'html/forms/TextFieldInputType.h',
             'html/forms/TextInputType.cpp',
             'html/forms/TextInputType.h',
             'html/forms/TimeInputType.cpp',
             'html/forms/TimeInputType.h',
             'html/forms/TypeAhead.cpp',
             'html/forms/TypeAhead.h',
             'html/forms/URLInputType.cpp',
             'html/forms/URLInputType.h',
-            'html/forms/ValidationMessage.cpp',
-            'html/forms/ValidationMessage.h',
             'html/forms/WeekInputType.cpp',
             'html/forms/WeekInputType.h',
             'html/ime/InputMethodContext.cpp',
             'html/ime/InputMethodContext.h',
             'html/imports/HTMLImport.cpp',
             'html/imports/HTMLImport.h',
             'html/imports/HTMLImportChild.cpp',
             'html/imports/HTMLImportChild.h',
             'html/imports/HTMLImportChildClient.h',
             'html/imports/HTMLImportLoader.cpp',
@@ skipping 732 matching lines @@
             'rendering/RenderOverflowTest.cpp',
             'rendering/RenderTableCellTest.cpp',
             'rendering/RenderTableRowTest.cpp',
             'rendering/shapes/BoxShapeTest.cpp',
             'testing/UnitTestHelpers.cpp',
             'testing/UnitTestHelpers.h',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }