[idd] serialize monitor replugs with swap chain teardown

Keep the replug lifecycle gated until the old swap chain has drained and
released its pending frame, and the replacement swap chain is fully
initialized. Coalesce additional requests into a follow-up replug to
prevent overlapping topology changes and IddCx release-frame timeout
bugchecks.

idd/LGIdd/CIndirectDeviceContext.h

@@ -64,10 +64,15 @@ private:
   IDDCX_ADAPTER m_adapter       = nullptr;
   IDDCX_MONITOR m_monitor       = nullptr;
   bool          m_replugMonitor = false;
+  bool          m_replugPending = false;
+  bool          m_monitorDeparted = false;
+  bool          m_swapChainAssigned = false;
+  bool          m_swapChainReady = false;
+  bool          m_waitForSwapChainRelease = false;
 
   // Guards the adapter/monitor init handshake and the replug state machine
-  // (m_monitor, m_replugMonitor, m_doSetMode, m_setMode). These are touched
-  // from the IddCx callback threads and the LGMP timer thread.
+  // (monitor/replug/swap-chain state, m_doSetMode, m_setMode). These are
+  // touched from the IddCx callback threads, swap-chain thread and LGMP timer.
   SRWLOCK m_stateLock = SRWLOCK_INIT;
 
   // Retry state for InitAdapter. At boot the IVSHMEM device may not have
@@ -166,6 +171,7 @@ private:
   // Set by ReplugMonitor after a departure to rebuild the monitor from the LGMP
   // timer, off the IddCx callback thread.
   volatile LONG m_finishInitQueued = 0;
+  volatile LONG m_replugQueued     = 0;
 
 public:
   CIndirectDeviceContext(_In_ WDFDEVICE wdfDevice) :
@@ -182,6 +188,9 @@ public:
 
   void OnMonitorDestroyed(IDDCX_MONITOR monitor);
   void OnAssignSwapChain();
+  void OnSwapChainAssigned();
+  void OnSwapChainReleased();
+  void OnSwapChainReady();
 
   NTSTATUS ParseMonitorDescription(
     const IDARG_IN_PARSEMONITORDESCRIPTION* inArgs, IDARG_OUT_PARSEMONITORDESCRIPTION* outArgs);