clang/win: Fix component build after https://codereview.chromium.org/1365003002

third_party/WebKit/Source/core/css/CSSBasicShapeValue.h

Index: third_party/WebKit/Source/core/css/CSSBasicShapeValue.h
diff --git a/third_party/WebKit/Source/core/css/CSSBasicShapeValue.h b/third_party/WebKit/Source/core/css/CSSBasicShapeValue.h
index 2b5397b36974ea4eeb1ebe722a1c8506ebc899d2..9bb1b4fa2556b816212101e1ead4714e4e455b1f 100644
--- a/third_party/WebKit/Source/core/css/CSSBasicShapeValue.h
+++ b/third_party/WebKit/Source/core/css/CSSBasicShapeValue.h
@@ -43,7 +43,7 @@ namespace blink {
 // TODO(Oilpan): the GC plugin is not capable of understanding that
 // the traceAfterDispatch() method covers subtypes of CSSBasicShapeValue.
 // Temporarily exempt it from being checked
-class CORE_EXPORT GC_PLUGIN_IGNORE("535448") CSSBasicShapeValue : public CSSValue {
+class GC_PLUGIN_IGNORE("535448") CORE_EXPORT CSSBasicShapeValue : public CSSValue {
 public:
     enum Type {
         CSSBasicShapeEllipseType,