Bug 888900 - Make sure the clipboard is always flushed at shutdown on win32 (r=jimm)

widget/windows/nsClipboard.cpp

@@ -32,6 +32,7 @@
 #include "nsCRT.h"
 #include "nsNetUtil.h"
 #include "nsEscape.h"
+#include "nsIObserverService.h"
 
 #ifdef PR_LOGGING
 PRLogModuleInfo* gWin32ClipboardLog = nullptr;
@@ -56,6 +57,13 @@ nsClipboard::nsClipboard() : nsBaseClipboard()
 
   mIgnoreEmptyNotification = false;
   mWindow         = nullptr;
+
+  // Register for a shutdown notification so that we can flush data
+ // to the OS clipboard.
+  nsCOMPtr<nsIObserverService> observerService =
+    do_GetService("@mozilla.org/observer-service;1");
+  if (observerService)
+    observerService->AddObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID, PR_FALSE);
 }
 
 //-------------------------------------------------------------------------
@@ -66,6 +74,19 @@ nsClipboard::~nsClipboard()
 
 }
 
+NS_IMPL_ISUPPORTS_INHERITED1(nsClipboard, nsBaseClipboard, nsIObserver)
+
+NS_IMETHODIMP
+nsClipboard::Observe(nsISupports *aSubject, const char *aTopic,
+                     const PRUnichar *aData)
+{
+  // This will be called on shutdown.
+  ::OleFlushClipboard();
+  ::CloseClipboard();
+
+  return NS_OK;
+}
+
 //-------------------------------------------------------------------------
 UINT nsClipboard::GetFormat(const char* aMimeStr)
 {

widget/windows/nsClipboard.h

@@ -20,13 +20,19 @@ struct IDataObject;
  * Native Win32 Clipboard wrapper
  */
 
-class nsClipboard : public nsBaseClipboard
+class nsClipboard : public nsBaseClipboard,
+                    public nsIObserver
 {
 
 public:
   nsClipboard();
   virtual ~nsClipboard();
 
+  NS_DECL_ISUPPORTS_INHERITED
+
+  // nsIObserver
+  NS_DECL_NSIOBSERVER
+
   // nsIClipboard
   NS_IMETHOD HasDataMatchingFlavors(const char** aFlavorList, uint32_t aLength,
                                     int32_t aWhichClipboard, bool *_retval);