[SPv2] Add CSS mask support

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

Index: third_party/WebKit/Source/core/css/FontFaceSet.h
diff --git a/third_party/WebKit/Source/core/css/FontFaceSet.h b/third_party/WebKit/Source/core/css/FontFaceSet.h
index 61b02bbe0f0defa7ae2d14fa55bddd1b8ff95967..dd8f57aef7d5fc2892dee91a73fda88d5b312f00 100644
--- a/third_party/WebKit/Source/core/css/FontFaceSet.h
+++ b/third_party/WebKit/Source/core/css/FontFaceSet.h
@@ -54,11 +54,11 @@ class ExecutionContext;
 
 using FontFaceSetIterable = PairIterable<Member<FontFace>, Member<FontFace>>;
 
-class FontFaceSet final : public EventTargetWithInlineData,
-                          public Supplement<Document>,
-                          public SuspendableObject,
-                          public FontFaceSetIterable,
-                          public FontFace::LoadFontCallback {
+class CORE_EXPORT FontFaceSet final : public EventTargetWithInlineData,
+                                      public Supplement<Document>,
+                                      public SuspendableObject,
+                                      public FontFaceSetIterable,
+                                      public FontFace::LoadFontCallback {
   USING_GARBAGE_COLLECTED_MIXIN(FontFaceSet);
   DEFINE_WRAPPERTYPEINFO();
   WTF_MAKE_NONCOPYABLE(FontFaceSet);