Componentization: fix SupplementTracing<0>::~SupplementTracing<0>(void) already defined.

Source/modules/encryptedmedia/MediaKeysController.h

Index: Source/modules/encryptedmedia/MediaKeysController.h
diff --git a/Source/modules/encryptedmedia/MediaKeysController.h b/Source/modules/encryptedmedia/MediaKeysController.h
index e3c7a230525fe8a31341048c8eb9e4f1bfd645eb..c0bb55488ef720afdf15081b28d42481910890c6 100644
--- a/Source/modules/encryptedmedia/MediaKeysController.h
+++ b/Source/modules/encryptedmedia/MediaKeysController.h
@@ -6,6 +6,7 @@
 #define MediaKeysController_h
 
 #include "core/page/Page.h"
+#include "core/page/PageSupplementable.h"
 #include "modules/ModulesExport.h"
 #include "wtf/PassOwnPtr.h"
 
@@ -13,6 +14,7 @@ namespace blink {
 
 class ExecutionContext;
 class MediaKeysClient;
+class Page;
 class WebContentDecryptionModule;
 class WebEncryptedMediaClient;