Backed out changeset 42d5d3080bc4 (bug 847656) for mochitest crashes on a CLOSED TREE.

dom/ipc/ContentParent.cpp

@@ -370,7 +370,7 @@ ContentParent::JoinAllSubprocesses()
     sCanLaunchSubprocesses = false;
 }
 
-/*static*/ already_AddRefed<ContentParent>
+/*static*/ ContentParent*
 ContentParent::GetNewOrUsed(bool aForBrowserElement)
 {
     if (!gNonAppContentParents)
@@ -394,7 +394,7 @@ ContentParent::GetNewOrUsed(bool aForBrowserElement)
                           PROCESS_PRIORITY_FOREGROUND);
     p->Init();
     gNonAppContentParents->AppendElement(p);
-    return p.forget();
+    return p;
 }
 
 namespace {
@@ -465,7 +465,7 @@ ContentParent::CreateBrowserOrApp(const TabContext& aContext,
     }
 
     if (aContext.IsBrowserElement() || !aContext.HasOwnApp()) {
-        if (nsRefPtr<ContentParent> cp = GetNewOrUsed(aContext.IsBrowserElement())) {
+        if (ContentParent* cp = GetNewOrUsed(aContext.IsBrowserElement())) {
             nsRefPtr<TabParent> tp(new TabParent(aContext));
             tp->SetOwnerElement(aFrameElement);
             PBrowserParent* browser = cp->SendPBrowserConstructor(

dom/ipc/ContentParent.h

@@ -81,8 +81,7 @@ public:
      */
     static void JoinAllSubprocesses();
 
-    static already_AddRefed<ContentParent>
+    static ContentParent* GetNewOrUsed(bool aForBrowserElement = false);
-    GetNewOrUsed(bool aForBrowserElement = false);
 
     /**
      * Get or create a content process for the given TabContext.  aFrameElement

toolkit/xre/nsAppRunner.cpp

@@ -780,7 +780,7 @@ nsXULAppInfo::EnsureContentProcess()
   if (XRE_GetProcessType() != GeckoProcessType_Default)
     return NS_ERROR_NOT_AVAILABLE;
 
-  nsRefPtr<ContentParent> unused = ContentParent::GetNewOrUsed();
+  unused << ContentParent::GetNewOrUsed();
   return NS_OK;
 }
 

toolkit/xre/nsEmbedFunctions.cpp

@@ -695,8 +695,7 @@ ContentParent* gContentParent; //long-lived, manually refcounted
 TestShellParent* GetOrCreateTestShellParent()
 {
     if (!gContentParent) {
-        nsRefPtr<ContentParent> parent = ContentParent::GetNewOrUsed().get();
+        NS_ADDREF(gContentParent = ContentParent::GetNewOrUsed());
-        parent.forget(&gContentParent);
     } else if (!gContentParent->IsAlive()) {
         return nullptr;
     }