Add exports needed for glue to build as a component.

webkit/extensions/v8/gc_extension.h

Index: webkit/extensions/v8/gc_extension.h
diff --git a/webkit/extensions/v8/gc_extension.h b/webkit/extensions/v8/gc_extension.h
index b34b1c3987f296ce1453f10477ed38da6cb69e46..ea5003be2d6e4cdb1a3bbe54c17133cc7f8688dd 100644
--- a/webkit/extensions/v8/gc_extension.h
+++ b/webkit/extensions/v8/gc_extension.h
@@ -6,6 +6,8 @@
 #define WEBKIT_EXTENSIONS_V8_GC_EXTENSION_H_
 #pragma once
 
+#include "webkit/extensions/webkit_extensions_export.h"
+
 namespace v8 {
 class Extension;
 }
@@ -16,7 +18,7 @@ namespace extensions_v8 {
 // garbage collection. This should only be used for debugging.
 class GCExtension {
  public:
-  static v8::Extension* Get();
+  WEBKIT_EXTENSIONS_EXPORT static v8::Extension* Get();
 };
 
 }  // namespace extensions_v8