Include Page.h in fewer headers

Source/core/workers/WorkerGlobalScopeProxyProvider.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 13 matching lines @@
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef WorkerGlobalScopeProxyProvider_h
 #define WorkerGlobalScopeProxyProvider_h
 
-#include "core/page/Page.h"
 #include "platform/Supplementable.h"
 #include "wtf/Forward.h"
 #include "wtf/Noncopyable.h"
 
-
 namespace WebCore {
 
+class Page;
 class WorkerGlobalScopeProxy;
 class Worker;
 
 class WorkerGlobalScopeProxyProvider : public WillBeHeapSupplement<Page> {
     WTF_MAKE_NONCOPYABLE(WorkerGlobalScopeProxyProvider);
 public:
     WorkerGlobalScopeProxyProvider() { }
     virtual ~WorkerGlobalScopeProxyProvider() { }
 
     virtual WorkerGlobalScopeProxy* createWorkerGlobalScopeProxy(Worker*) = 0;
 
     static WorkerGlobalScopeProxyProvider* from(Page&);
     static const char* supplementName();
 };
 
 void provideWorkerGlobalScopeProxyProviderTo(Page&, PassOwnPtrWillBeRawPtr<WorkerGlobalScopeProxyProvider>);
 
 } // namespace WebCore
 
 #endif // WorkerGlobalScopeProxyProvider_h