[H] Expose unlink ghost windows to about:memory

dom/base/nsGlobalWindow.cpp

@@ -2300,13 +2300,11 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(nsGlobalWindow)
   NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
 
-#ifdef DEBUG
 void
 nsGlobalWindow::RiskyUnlink()
 {
   NS_CYCLE_COLLECTION_INNERNAME.Unlink(this);
 }
-#endif
 
 NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(nsGlobalWindow)
   if (tmp->mCachedXBLPrototypeHandlers) {

dom/base/nsGlobalWindow.h

@@ -597,11 +597,9 @@ public:
   NS_DECL_CYCLE_COLLECTION_SKIPPABLE_SCRIPT_HOLDER_CLASS_AMBIGUOUS(nsGlobalWindow,
                                                                    nsIDOMEventTarget)
 
-#ifdef DEBUG
   // Call Unlink on this window. This may cause bad things to happen, so use
   // with caution.
   void RiskyUnlink();
-#endif
 
   virtual JSObject*
     GetCachedXBLPrototypeHandler(nsXBLPrototypeHandler* aKey) override;

dom/base/nsWindowMemoryReporter.cpp

@@ -829,7 +829,6 @@ nsWindowMemoryReporter::KillCheckTimer()
   }
 }
 
-#ifdef DEBUG
 /* static */ void
 nsWindowMemoryReporter::UnlinkGhostWindows()
 {
@@ -866,4 +865,3 @@ nsWindowMemoryReporter::UnlinkGhostWindows()
     }
   }
 }
-#endif

dom/base/nsWindowMemoryReporter.h

@@ -150,13 +150,11 @@ public:
 
   static void Init();
 
-#ifdef DEBUG
   /**
    * Unlink all known ghost windows, to enable investigating what caused them
    * to become ghost windows in the first place.
    */
   static void UnlinkGhostWindows();
-#endif
 
   static nsWindowMemoryReporter* Get();
   void ObserveDOMWindowDetached(nsGlobalWindow* aWindow);

js/xpconnect/src/XPCComponents.cpp

@@ -2664,12 +2664,8 @@ nsXPCComponents_Utils::SchedulePreciseShrinkingGC(ScheduledGCCallback* aCallback
 NS_IMETHODIMP
 nsXPCComponents_Utils::UnlinkGhostWindows()
 {
-#ifdef DEBUG
     nsWindowMemoryReporter::UnlinkGhostWindows();
     return NS_OK;
-#else
-    return NS_ERROR_NOT_IMPLEMENTED;
-#endif
 }
 
 NS_IMETHODIMP

toolkit/components/aboutmemory/content/aboutMemory.js

@@ -304,6 +304,9 @@ function onLoad()
                  "collection followed by a cycle collection, and causes the " +
                  "process to reduce memory usage in other ways, e.g. by " +
                  "flushing various caches.";
+  const UGDesc = "Unlink any known ghost windows, to enable investigating " +
+                 "what caused them. This is only for debugging leaks, and " +
+                 "can cause bad things to happen if called.";
 
   const GCAndCCLogDesc = "Save garbage collection log and concise cycle " +
                          "collection log.\n" +
@@ -357,6 +360,7 @@ function onLoad()
   appendButton(row3, GCDesc, doGC,  "GC");
   appendButton(row3, CCDesc, doCC,  "CC");
   appendButton(row3, MMDesc, doMMU, "Minimize memory usage");
+  appendButton(row3, UGDesc, doUGW, "Unlink ghost windows");
 
   let row4 = appendElement(ops, "div", "opsRow");
 
@@ -429,6 +433,12 @@ function doMMU()
     () => updateMainAndFooter("Memory minimization completed", HIDE_FOOTER));
 }
 
+function doUGW()
+{
+  Cu.unlinkGhostWindows();
+  updateMainAndFooter("Unlink ghost windows completed", HIDE_FOOTER);
+}
+
 function doMeasure()
 {
   updateAboutMemoryFromReporters();