Bug 1024470 - Make sure we run InitOnContentProcessCreated in all cases. r=khuey

dom/ipc/ContentChild.cpp

@@ -482,8 +482,17 @@ ContentChild* ContentChild::sSingleton;
 // Performs initialization that is not fork-safe, i.e. that must be done after
 // forking from the Nuwa process.
 static void
-InitOnContentProcessCreated()
+InitOnContentProcessCreated(bool aAfterNuwaFork)
 {
+#ifdef MOZ_NUWA_PROCESS
+    // Wait until we are forked from Nuwa
+    if (!aAfterNuwaFork &&
+        Preferences::GetBool("dom.ipc.processPrelaunch.enabled", false)) {
+        return;
+    }
+#else
+    unused << aAfterNuwaFork;
+#endif
     // This will register cross-process observer.
     mozilla::dom::time::InitializeDateCacheCleaner();
 }
@@ -670,9 +679,7 @@ ContentChild::InitXPCOM()
         new SystemMessageHandledObserver();
     sysMsgObserver->Init();
 
-#ifndef MOZ_NUWA_PROCESS
-    InitOnContentProcessCreated();
-#endif
+    InitOnContentProcessCreated(/* aAfterNuwaFork = */false);
 }
 
 PMemoryReportRequestChild*
@@ -1843,7 +1850,7 @@ public:
         }
 
         // Perform other after-fork initializations.
-        InitOnContentProcessCreated();
+        InitOnContentProcessCreated(/* aAfterNuwaFork = */true);
 
         return NS_OK;
     }

dom/ipc/ContentParent.cpp

@@ -602,23 +602,28 @@ ContentParent::MaybeTakePreallocatedAppProcess(const nsAString& aAppManifestURL,
 /*static*/ void
 ContentParent::StartUp()
 {
+    // We could launch sub processes from content process
+    // FIXME Bug 1023701 - Stop using ContentParent static methods in
+    // child process
+    sCanLaunchSubprocesses = true;
+
+    if (XRE_GetProcessType() != GeckoProcessType_Default) {
+        return;
+    }
+
     // Note: This reporter measures all ContentParents.
     RegisterStrongMemoryReporter(new ContentParentsMemoryReporter());
 
     mozilla::dom::time::InitializeDateCacheCleaner();
 
-    sCanLaunchSubprocesses = true;
+    BackgroundChild::Startup();
 
-    if (XRE_GetProcessType() == GeckoProcessType_Default) {
-        BackgroundChild::Startup();
+    // Try to preallocate a process that we can transform into an app later.
+    PreallocatedProcessManager::AllocateAfterDelay();
 
-        // Try to preallocate a process that we can transform into an app later.
-        PreallocatedProcessManager::AllocateAfterDelay();
-
-        // Test the PBackground infrastructure on ENABLE_TESTS builds when a special
-        // testing preference is set.
-        MaybeTestPBackground();
-    }
+    // Test the PBackground infrastructure on ENABLE_TESTS builds when a special
+    // testing preference is set.
+    MaybeTestPBackground();
 }
 
 /*static*/ void