Cherry-pick 272448.445@safari-7618-branch (b60b2da). rdar://107918233

    Block "setMediaOverridesForTesting" media IPC endpoints when not testing
    rdar://107918233

    Reviewed by Youenn Fablet.

    This is a continuation of 260935@main, adding the setMediaOverridesForTesting to the list
    of blocked IPC endpoints.

    All involved tests already contains the required keywords.

    * Source/WebKit/GPUProcess/GPUConnectionToWebProcess.messages.in:

    Canonical link: https://commits.webkit.org/272448.445@safari-7618-branch

Canonical link: https://commits.webkit.org/266719.412@webkitglib/2.42

Source/WebKit/GPUProcess/GPUConnectionToWebProcess.messages.in

@@ -47,7 +47,7 @@ messages -> GPUConnectionToWebProcess WantsDispatchMessage {
     CreateVisibilityPropagationContextForPage(WebKit::WebPageProxyIdentifier pageProxyID, WebCore::PageIdentifier pageID, bool canShowWhileLocked);
     DestroyVisibilityPropagationContextForPage(WebKit::WebPageProxyIdentifier pageProxyID, WebCore::PageIdentifier pageID);
 #endif
-    SetMediaOverridesForTesting(struct WebKit::MediaOverridesForTesting configuration)
+    [EnabledIf='allowTestOnlyIPC()'] SetMediaOverridesForTesting(struct WebKit::MediaOverridesForTesting configuration)
     CreateAudioHardwareListener(WebKit::RemoteAudioHardwareListenerIdentifier identifier)
     ReleaseAudioHardwareListener(WebKit::RemoteAudioHardwareListenerIdentifier identifier)
     CreateRemoteCommandListener(WebKit::RemoteRemoteCommandListenerIdentifier identifier)