Move PopupMenuClient.h to core/html/forms

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/AnimationNode.idl',
@@ skipping 2756 matching lines @@
             'html/forms/InputType.cpp',
             'html/forms/InputType.h',
             'html/forms/InputTypeView.cpp',
             'html/forms/InputTypeView.h',
             'html/forms/MonthInputType.cpp',
             'html/forms/MonthInputType.h',
             'html/forms/NumberInputType.cpp',
             'html/forms/NumberInputType.h',
             'html/forms/PasswordInputType.cpp',
             'html/forms/PasswordInputType.h',
+            'html/forms/PopupMenuClient.h',
             'html/forms/RadioButtonGroupScope.cpp',
             'html/forms/RadioButtonGroupScope.h',
             'html/forms/RadioInputType.cpp',
             'html/forms/RadioInputType.h',
             'html/forms/RangeInputType.cpp',
             'html/forms/RangeInputType.h',
             'html/forms/ResetInputType.cpp',
             'html/forms/ResetInputType.h',
             'html/forms/SearchInputType.cpp',
             'html/forms/SearchInputType.h',
@@ skipping 808 matching lines @@
             'rendering/style/OutlineValueTest.cpp',
             'rendering/style/RenderStyleTest.cpp',
             'streams/ReadableStreamTest.cpp',
             'testing/PrivateScriptTestTest.cpp',
             'testing/UnitTestHelpers.cpp',
             'testing/UnitTestHelpers.h',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }