Bug 722428: Fix leaks in mochitest by reworking SpecialPowers and nsDOMWindowUtils. r=mounir,ctalbert

dom/base/nsDOMWindowUtils.cpp

@@ -107,29 +107,21 @@ static bool IsUniversalXPConnectCapable()
 
 DOMCI_DATA(WindowUtils, nsDOMWindowUtils)
 
-NS_IMPL_CYCLE_COLLECTION_CLASS(nsDOMWindowUtils)
-NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(nsDOMWindowUtils)
-  NS_IMPL_CYCLE_COLLECTION_UNLINK_NSCOMPTR(mWindow)
-NS_IMPL_CYCLE_COLLECTION_UNLINK_END
-NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(nsDOMWindowUtils)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE_NSCOMPTR_AMBIGUOUS(mWindow,
-                                                       nsIScriptGlobalObject)
-NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
-
-NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsDOMWindowUtils)
+NS_INTERFACE_MAP_BEGIN(nsDOMWindowUtils)
   NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIDOMWindowUtils)
   NS_INTERFACE_MAP_ENTRY(nsIDOMWindowUtils)
   NS_INTERFACE_MAP_ENTRY(nsISupportsWeakReference)
   NS_DOM_INTERFACE_MAP_ENTRY_CLASSINFO(WindowUtils)
 NS_INTERFACE_MAP_END
 
-NS_IMPL_CYCLE_COLLECTING_ADDREF(nsDOMWindowUtils)
-NS_IMPL_CYCLE_COLLECTING_RELEASE(nsDOMWindowUtils)
+NS_IMPL_ADDREF(nsDOMWindowUtils)
+NS_IMPL_RELEASE(nsDOMWindowUtils)
 
 nsDOMWindowUtils::nsDOMWindowUtils(nsGlobalWindow *aWindow)
-  : mWindow(aWindow)
 {
-  NS_ASSERTION(mWindow->IsOuterWindow(), "How did that happen?");
+  nsCOMPtr<nsISupports> supports = do_QueryObject(aWindow);
+  mWindow = do_GetWeakReference(supports);
+  NS_ASSERTION(aWindow->IsOuterWindow(), "How did that happen?");
 }
 
 nsDOMWindowUtils::~nsDOMWindowUtils()
@@ -139,10 +131,11 @@ nsDOMWindowUtils::~nsDOMWindowUtils()
 nsIPresShell*
 nsDOMWindowUtils::GetPresShell()
 {
-  if (!mWindow)
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  if (!window)
     return nsnull;
 
-  nsIDocShell *docShell = mWindow->GetDocShell();
+  nsIDocShell *docShell = window->GetDocShell();
   if (!docShell)
     return nsnull;
 
@@ -154,9 +147,10 @@ nsDOMWindowUtils::GetPresShell()
 nsPresContext*
 nsDOMWindowUtils::GetPresContext()
 {
-  if (!mWindow)
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  if (!window)
     return nsnull;
-  nsIDocShell *docShell = mWindow->GetDocShell();
+  nsIDocShell *docShell = window->GetDocShell();
   if (!docShell)
     return nsnull;
   nsRefPtr<nsPresContext> presContext;
@@ -197,8 +191,9 @@ nsDOMWindowUtils::GetDocCharsetIsForced(bool *aIsForced)
     return NS_ERROR_DOM_SECURITY_ERR;
   }
 
-  if (mWindow) {
-    nsCOMPtr<nsIDocument> doc(do_QueryInterface(mWindow->GetExtantDocument()));
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  if (window) {
+    nsCOMPtr<nsIDocument> doc(do_QueryInterface(window->GetExtantDocument()));
     *aIsForced = doc &&
       doc->GetDocumentCharacterSetSource() >= kCharsetFromParentForced;
   }
@@ -213,8 +208,9 @@ nsDOMWindowUtils::GetDocumentMetadata(const nsAString& aName,
     return NS_ERROR_DOM_SECURITY_ERR;
   }
 
-  if (mWindow) {
-    nsCOMPtr<nsIDocument> doc(do_QueryInterface(mWindow->GetExtantDocument()));
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  if (window) {
+    nsCOMPtr<nsIDocument> doc(do_QueryInterface(window->GetExtantDocument()));
     if (doc) {
       nsCOMPtr<nsIAtom> name = do_GetAtom(aName);
       doc->GetHeaderData(name, aValue);
@@ -810,8 +806,9 @@ nsDOMWindowUtils::ForceUpdateNativeMenuAt(const nsAString& indexString)
 nsIWidget*
 nsDOMWindowUtils::GetWidget(nsPoint* aOffset)
 {
-  if (mWindow) {
-    nsIDocShell *docShell = mWindow->GetDocShell();
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  if (window) {
+    nsIDocShell *docShell = window->GetDocShell();
     if (docShell) {
       nsCOMPtr<nsIPresShell> presShell;
       docShell->GetPresShell(getter_AddRefs(presShell));
@@ -855,12 +852,13 @@ nsDOMWindowUtils::Focus(nsIDOMElement* aElement)
     return NS_ERROR_DOM_SECURITY_ERR;
   }
 
+  nsCOMPtr<nsIDOMWindow> window = do_QueryReferent(mWindow);
   nsIFocusManager* fm = nsFocusManager::GetFocusManager();
   if (fm) {
     if (aElement)
       fm->SetFocus(aElement, 0);
     else
-      fm->ClearFocus(mWindow);
+      fm->ClearFocus(window);
   }
 
   return NS_OK;
@@ -968,7 +966,10 @@ nsDOMWindowUtils::ElementFromPoint(float aX, float aY,
                                    bool aFlushLayout,
                                    nsIDOMElement** aReturn)
 {
-  nsCOMPtr<nsIDocument> doc(do_QueryInterface(mWindow->GetExtantDocument()));
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  NS_ENSURE_STATE(window);
+
+  nsCOMPtr<nsIDocument> doc(do_QueryInterface(window->GetExtantDocument()));
   NS_ENSURE_STATE(doc);
 
   return doc->ElementFromPointHelper(aX, aY, aIgnoreRootScrollFrame, aFlushLayout,
@@ -987,7 +988,10 @@ nsDOMWindowUtils::NodesFromRect(float aX, float aY,
     return NS_ERROR_DOM_SECURITY_ERR;
   }
 
-  nsCOMPtr<nsIDocument> doc(do_QueryInterface(mWindow->GetExtantDocument()));
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  NS_ENSURE_STATE(window);
+
+  nsCOMPtr<nsIDocument> doc(do_QueryInterface(window->GetExtantDocument()));
   NS_ENSURE_STATE(doc);
 
   return doc->NodesFromRectHelper(aX, aY, aTopSize, aRightSize, aBottomSize, aLeftSize, 
@@ -1110,8 +1114,9 @@ nsDOMWindowUtils::DisableNonTestMouseEvents(bool aDisable)
     return NS_ERROR_DOM_SECURITY_ERR;
   }
 
-  NS_ENSURE_TRUE(mWindow, NS_ERROR_FAILURE);
-  nsIDocShell *docShell = mWindow->GetDocShell();
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  NS_ENSURE_TRUE(window, NS_ERROR_FAILURE);
+  nsIDocShell *docShell = window->GetDocShell();
   NS_ENSURE_TRUE(docShell, NS_ERROR_FAILURE);
   nsCOMPtr<nsIPresShell> presShell;
   docShell->GetPresShell(getter_AddRefs(presShell));
@@ -1127,7 +1132,10 @@ nsDOMWindowUtils::SuppressEventHandling(bool aSuppress)
     return NS_ERROR_DOM_SECURITY_ERR;
   }
 
-  nsCOMPtr<nsIDocument> doc(do_QueryInterface(mWindow->GetExtantDocument()));
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  NS_ENSURE_STATE(window);
+
+  nsCOMPtr<nsIDocument> doc(do_QueryInterface(window->GetExtantDocument()));
   NS_ENSURE_TRUE(doc, NS_ERROR_FAILURE);
 
   if (aSuppress) {
@@ -1142,7 +1150,10 @@ nsDOMWindowUtils::SuppressEventHandling(bool aSuppress)
 NS_IMETHODIMP
 nsDOMWindowUtils::GetScrollXY(bool aFlushLayout, PRInt32* aScrollX, PRInt32* aScrollY)
 {
-  nsCOMPtr<nsIDocument> doc(do_QueryInterface(mWindow->GetExtantDocument()));
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  NS_ENSURE_STATE(window);
+
+  nsCOMPtr<nsIDocument> doc(do_QueryInterface(window->GetExtantDocument()));
   NS_ENSURE_STATE(doc);
 
   if (aFlushLayout) {
@@ -1421,9 +1432,10 @@ nsDOMWindowUtils::SendQueryContentEvent(PRUint32 aType,
     return NS_ERROR_DOM_SECURITY_ERR;
   }
 
-  NS_ENSURE_TRUE(mWindow, NS_ERROR_FAILURE);
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  NS_ENSURE_TRUE(window, NS_ERROR_FAILURE);
 
-  nsIDocShell *docShell = mWindow->GetDocShell();
+  nsIDocShell *docShell = window->GetDocShell();
   NS_ENSURE_TRUE(docShell, NS_ERROR_FAILURE);
 
   nsCOMPtr<nsIPresShell> presShell;
@@ -1603,9 +1615,12 @@ nsDOMWindowUtils::GetVisitedDependentComputedStyle(
     return NS_ERROR_DOM_SECURITY_ERR;
   }
 
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  NS_ENSURE_STATE(window);
+
   nsCOMPtr<nsIDOMCSSStyleDeclaration> decl;
   nsresult rv =
-    mWindow->GetComputedStyle(aElement, aPseudoElement, getter_AddRefs(decl));
+    window->GetComputedStyle(aElement, aPseudoElement, getter_AddRefs(decl));
   NS_ENSURE_SUCCESS(rv, rv);
 
   static_cast<nsComputedDOMStyle*>(decl.get())->SetExposeVisitedStyle(true);
@@ -1618,21 +1633,30 @@ nsDOMWindowUtils::GetVisitedDependentComputedStyle(
 NS_IMETHODIMP
 nsDOMWindowUtils::EnterModalState()
 {
-  mWindow->EnterModalState();
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  NS_ENSURE_STATE(window);
+
+  window->EnterModalState();
   return NS_OK;
 }
 
 NS_IMETHODIMP
 nsDOMWindowUtils::LeaveModalState()
 {
-  mWindow->LeaveModalState(nsnull);
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  NS_ENSURE_STATE(window);
+
+  window->LeaveModalState(nsnull);
   return NS_OK;
 }
 
 NS_IMETHODIMP
 nsDOMWindowUtils::EnterModalStateWithWindow(nsIDOMWindow **aWindow)
 {
-  *aWindow = mWindow->EnterModalState();
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  NS_ENSURE_STATE(window);
+
+  *aWindow = window->EnterModalState();
   NS_IF_ADDREF(*aWindow);
   return NS_OK;
 }
@@ -1640,15 +1664,21 @@ nsDOMWindowUtils::EnterModalStateWithWindow(nsIDOMWindow **aWindow)
 NS_IMETHODIMP
 nsDOMWindowUtils::LeaveModalStateWithWindow(nsIDOMWindow *aWindow)
 {
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  NS_ENSURE_STATE(window);
+
   NS_ENSURE_ARG_POINTER(aWindow);
-  mWindow->LeaveModalState(aWindow);
+  window->LeaveModalState(aWindow);
   return NS_OK;
 }
 
 NS_IMETHODIMP
 nsDOMWindowUtils::IsInModalState(bool *retval)
 {
-  *retval = mWindow->IsInModalState();
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  NS_ENSURE_STATE(window);
+
+  *retval = static_cast<nsGlobalWindow*>(window.get())->IsInModalState();
   return NS_OK;
 }
 
@@ -1683,16 +1713,23 @@ nsDOMWindowUtils::GetParent(const JS::Value& aObject,
 NS_IMETHODIMP
 nsDOMWindowUtils::GetOuterWindowID(PRUint64 *aWindowID)
 {
-  NS_ASSERTION(mWindow->IsOuterWindow(), "How did that happen?");
-  *aWindowID = mWindow->WindowID();
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  NS_ENSURE_STATE(window);
+
+  NS_ASSERTION(window->IsOuterWindow(), "How did that happen?");
+  *aWindowID = window->WindowID();
   return NS_OK;
 }
 
 NS_IMETHODIMP
 nsDOMWindowUtils::GetCurrentInnerWindowID(PRUint64 *aWindowID)
 {
-  NS_ASSERTION(mWindow->IsOuterWindow(), "How did that happen?");
-  nsGlobalWindow* inner = mWindow->GetCurrentInnerWindowInternal();
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  NS_ENSURE_TRUE(window, NS_ERROR_NOT_AVAILABLE);
+
+  NS_ASSERTION(window->IsOuterWindow(), "How did that happen?");
+  nsGlobalWindow* inner =
+    static_cast<nsGlobalWindow*>(window.get())->GetCurrentInnerWindowInternal();
   if (!inner) {
     return NS_ERROR_NOT_AVAILABLE;
   }
@@ -1707,7 +1744,10 @@ nsDOMWindowUtils::SuspendTimeouts()
     return NS_ERROR_DOM_SECURITY_ERR;
   }
 
-  mWindow->SuspendTimeouts();
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  NS_ENSURE_TRUE(window, NS_ERROR_FAILURE);
+
+  window->SuspendTimeouts();
 
   return NS_OK;
 }
@@ -1719,7 +1759,10 @@ nsDOMWindowUtils::ResumeTimeouts()
     return NS_ERROR_DOM_SECURITY_ERR;
   }
 
-  mWindow->ResumeTimeouts();
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  NS_ENSURE_TRUE(window, NS_ERROR_FAILURE);
+
+  window->ResumeTimeouts();
 
   return NS_OK;
 }
@@ -1888,10 +1931,13 @@ nsDOMWindowUtils::RenderDocument(const nsRect& aRect,
                                  nscolor aBackgroundColor,
                                  gfxContext* aThebesContext)
 {
+    nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+    NS_ENSURE_TRUE(window, NS_ERROR_FAILURE);
+
     // Get DOM Document
     nsresult rv;
     nsCOMPtr<nsIDOMDocument> ddoc;
-    rv = mWindow->GetDocument(getter_AddRefs(ddoc));
+    rv = window->GetDocument(getter_AddRefs(ddoc));
     NS_ENSURE_SUCCESS(rv, rv);
 
     // Get Document
@@ -1911,8 +1957,11 @@ nsDOMWindowUtils::GetCursorType(PRInt16 *aCursor)
 {
   NS_ENSURE_ARG_POINTER(aCursor);
 
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  NS_ENSURE_TRUE(window, NS_ERROR_FAILURE);  
+
   bool isSameDoc = false;
-  nsCOMPtr<nsIDocument> doc(do_QueryInterface(mWindow->GetExtantDocument()));
+  nsCOMPtr<nsIDocument> doc(do_QueryInterface(window->GetExtantDocument()));
 
   NS_ENSURE_TRUE(doc, NS_ERROR_FAILURE);
 
@@ -1943,8 +1992,9 @@ nsDOMWindowUtils::GoOnline()
 {
   // This is only allowed from about:neterror, which is unprivileged, so it
   // can't access the io-service itself.
-  NS_ENSURE_TRUE(mWindow, NS_ERROR_FAILURE);
-  nsCOMPtr<nsIDocument> doc(do_QueryInterface(mWindow->GetExtantDocument()));
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  NS_ENSURE_TRUE(window, NS_ERROR_FAILURE);
+  nsCOMPtr<nsIDocument> doc(do_QueryInterface(window->GetExtantDocument()));
   NS_ENSURE_TRUE(doc, NS_ERROR_FAILURE);
   nsCOMPtr<nsIURI> documentURI;
   documentURI = doc->GetDocumentURI();
@@ -2068,7 +2118,10 @@ nsDOMWindowUtils::GetMayHaveTouchEventListeners(bool* aResult)
     return NS_ERROR_DOM_SECURITY_ERR;
   }
 
-  nsPIDOMWindow* innerWindow = mWindow->GetCurrentInnerWindow();
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  NS_ENSURE_TRUE(window, NS_ERROR_FAILURE);
+
+  nsPIDOMWindow* innerWindow = window->GetCurrentInnerWindow();
   *aResult = innerWindow ? innerWindow->HasTouchEventListeners() : false;
   return NS_OK;
 }
@@ -2116,11 +2169,12 @@ nsDOMWindowUtils::GetFileReferences(const nsAString& aDatabaseName,
     return NS_ERROR_DOM_SECURITY_ERR;
   }
 
-  NS_ENSURE_TRUE(mWindow, NS_ERROR_FAILURE);
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  NS_ENSURE_TRUE(window, NS_ERROR_FAILURE);
 
   nsCString origin;
   nsresult rv = indexedDB::IndexedDatabaseManager::GetASCIIOriginFromWindow(
-    mWindow, origin);
+    window, origin);
   NS_ENSURE_SUCCESS(rv, rv);
 
   nsRefPtr<indexedDB::IndexedDatabaseManager> mgr =
@@ -2220,8 +2274,9 @@ nsDOMWindowUtils::GetPCCountScriptContents(PRInt32 script, JSContext* cx, nsAStr
 NS_IMETHODIMP
 nsDOMWindowUtils::GetPaintingSuppressed(bool *aPaintingSuppressed)
 {
-  NS_ENSURE_TRUE(mWindow, NS_ERROR_FAILURE);
-  nsIDocShell *docShell = mWindow->GetDocShell();
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  NS_ENSURE_TRUE(window, NS_ERROR_FAILURE);
+  nsIDocShell *docShell = window->GetDocShell();
   NS_ENSURE_TRUE(docShell, NS_ERROR_FAILURE);
 
   nsCOMPtr<nsIPresShell> presShell;
@@ -2239,7 +2294,10 @@ nsDOMWindowUtils::GetPlugins(JSContext* cx, jsval* aPlugins)
     return NS_ERROR_DOM_SECURITY_ERR;
   }
 
-  nsIDOMDocument* ddoc = mWindow->GetExtantDocument();
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  NS_ENSURE_STATE(window);
+
+  nsIDOMDocument* ddoc = window->GetExtantDocument();
 
   nsresult rv;
   nsCOMPtr<nsIDocument> doc = do_QueryInterface(ddoc, &rv);

dom/base/nsDOMWindowUtils.h

@@ -49,13 +49,11 @@ class nsDOMWindowUtils : public nsIDOMWindowUtils,
 public:
   nsDOMWindowUtils(nsGlobalWindow *aWindow);
   ~nsDOMWindowUtils();
-  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
-  NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(nsDOMWindowUtils,
-                                           nsIDOMWindowUtils)
+  NS_DECL_ISUPPORTS
   NS_DECL_NSIDOMWINDOWUTILS
 
 protected:
-  nsRefPtr<nsGlobalWindow> mWindow;
+  nsWeakPtr mWindow;
 
   // If aOffset is non-null, it gets filled in with the offset of the root
   // frame of our window to the nearest widget in the app units of our window.

dom/base/nsGlobalWindow.cpp

@@ -1224,6 +1224,7 @@ nsGlobalWindow::CleanUp(bool aIgnoreModalDialog)
   mLocation = nsnull;
   mHistory = nsnull;
   mFrames = nsnull;
+  mWindowUtils = nsnull;
   mApplicationCache = nsnull;
   mIndexedDB = nsnull;
   mPendingStorageEventsObsolete = nsnull;
@@ -8368,20 +8369,12 @@ nsGlobalWindow::GetInterface(const nsIID & aIID, void **aSink)
   else if (aIID.Equals(NS_GET_IID(nsIDOMWindowUtils))) {
     FORWARD_TO_OUTER(GetInterface, (aIID, aSink), NS_ERROR_NOT_INITIALIZED);
 
-    nsCOMPtr<nsISupports> utils(do_QueryReferent(mWindowUtils));
-    if (utils) {
-      *aSink = utils;
-      NS_ADDREF(((nsISupports *) *aSink));
-    } else {
-      nsDOMWindowUtils *utilObj = new nsDOMWindowUtils(this);
-      nsCOMPtr<nsISupports> utilsIfc =
-                              NS_ISUPPORTS_CAST(nsIDOMWindowUtils *, utilObj);
-      if (utilsIfc) {
-        mWindowUtils = do_GetWeakReference(utilsIfc);
-        *aSink = utilsIfc;
-        NS_ADDREF(((nsISupports *) *aSink));
-      }
+    if (!mWindowUtils) {
+      mWindowUtils = new nsDOMWindowUtils(this);
     }
+
+    *aSink = mWindowUtils;
+    NS_ADDREF(((nsISupports *) *aSink));
   }
   else {
     return QueryInterface(aIID, aSink);

dom/base/nsGlobalWindow.h

@@ -136,6 +136,7 @@ class nsRunnable;
 class nsDOMEventTargetHelper;
 class nsDOMOfflineResourceList;
 class nsDOMMozURLProperty;
+class nsDOMWindowUtils;
 
 #ifdef MOZ_DISABLE_DOMCRYPTO
 class nsIDOMCrypto;
@@ -896,7 +897,7 @@ protected:
   nsRefPtr<nsBarProp>           mPersonalbar;
   nsRefPtr<nsBarProp>           mStatusbar;
   nsRefPtr<nsBarProp>           mScrollbars;
-  nsCOMPtr<nsIWeakReference>    mWindowUtils;
+  nsRefPtr<nsDOMWindowUtils>    mWindowUtils;
   nsString                      mStatus;
   nsString                      mDefaultStatus;
   // index 0->language_id 1, so index MAX-1 == language_id MAX

testing/mochitest/specialpowers/content/specialpowers.js

@@ -39,7 +39,7 @@
  */
 
 function SpecialPowers(window) {
-  this.window = window;
+  this.window = Components.utils.getWeakReference(window);
   this._encounteredCrashDumpFiles = [];
   this._unexpectedCrashDumpFiles = { };
   this._crashDumpDir = null;

testing/mochitest/tests/SimpleTest/ChromePowers.js

@@ -36,13 +36,13 @@
  * ***** END LICENSE BLOCK ***** */
 
 function ChromePowers(window) {
-  this.window = window;
+  this.window = Components.utils.getWeakReference(window);
 
   // In the case of browser-chrome tests, we are running as a [ChromeWindow]
   // and we have no window.QueryInterface available, content.window is what we need
   if (typeof(window) == "ChromeWindow" && typeof(content.window) == "Window") {
     this.DOMWindowUtils = bindDOMWindowUtils(content.window);
-    this.window = content.window
+    this.window = Components.utils.getWeakReference(content.window);
   } else {
     this.DOMWindowUtils = bindDOMWindowUtils(window);
   }

testing/mochitest/tests/SimpleTest/specialpowersAPI.js

@@ -77,7 +77,9 @@ function bindDOMWindowUtils(aWindow) {
     if (prop in desc && typeof(desc[prop]) == "function") {
       var oldval = desc[prop];
       try {
-        desc[prop] = function() { return oldval.apply(util, arguments); };
+        desc[prop] = function() {
+          return oldval.apply(util, arguments);
+        };
       } catch (ex) {
         dump("WARNING: Special Powers failed to rebind function: " + desc + "::" + prop + "\n");
       }
@@ -387,7 +389,7 @@ SpecialPowersAPI.prototype = {
   },
 
   getDOMWindowUtils: function(aWindow) {
-    if (aWindow == this.window && this.DOMWindowUtils != null)
+    if (aWindow == this.window.get() && this.DOMWindowUtils != null)
       return this.DOMWindowUtils;
 
     return bindDOMWindowUtils(aWindow);
@@ -774,7 +776,7 @@ SpecialPowersAPI.prototype = {
   },
 
   snapshotWindow: function (win, withCaret) {
-    var el = this.window.document.createElementNS("http://www.w3.org/1999/xhtml", "canvas");
+    var el = this.window.get().document.createElementNS("http://www.w3.org/1999/xhtml", "canvas");
     el.width = win.innerWidth;
     el.height = win.innerHeight;
     var ctx = el.getContext("2d");
@@ -1002,7 +1004,7 @@ SpecialPowersAPI.prototype = {
   },
 
   snapshotWindow: function (win, withCaret) {
-    var el = this.window.document.createElementNS("http://www.w3.org/1999/xhtml", "canvas");
+    var el = this.window.get().document.createElementNS("http://www.w3.org/1999/xhtml", "canvas");
     el.width = win.innerWidth;
     el.height = win.innerHeight;
     var ctx = el.getContext("2d");