Add option to delay showing main frame at startup

#rb chris.gagnon


#ROBOMERGE-SOURCE: CL 11672298 via CL 11672319 via CL 11672336
#ROBOMERGE-BOT: (v656-11643781)

[CL 11863430 by rex hill in Main branch]

Engine/Source/Editor/MainFrame/Public/Interfaces/IMainFrameModule.h

@@ -178,6 +178,16 @@ public:
 	virtual FMainFrameSDKNotInstalled& OnMainFrameSDKNotInstalled( ) = 0;
 	virtual void BroadcastMainFrameSDKNotInstalled(const FString& PlatformName, const FString& DocLink) = 0;
 
+	/**
+	 * Enable external control of when main frame is shown
+	 */
+	virtual void EnableDelayedShowMainFrame() = 0;
+
+	/**
+	 * Show main frame now if it was delayed and not shown yet
+	 */
+	virtual void ShowDelayedMainFrame() = 0;
+
 public:
 
 	/**