b=545237 Keep track of the ContentProcessParent singleton's life and recreate it if necessary r=bsmedberg

content/base/src/nsFrameLoader.cpp

@@ -1542,7 +1542,9 @@ nsFrameLoader::TryNewProcess()
     return false;
   }
 
-  mChildProcess = ContentProcessParent::GetSingleton()->CreateTab();
+  ContentProcessParent* parent = ContentProcessParent::GetSingleton();
+  NS_ASSERTION(parent->IsAlive(), "Process parent should be alive; something is very wrong!");
+  mChildProcess = parent->CreateTab();
   if (mChildProcess) {
     nsCOMPtr<nsIDOMElement> element = do_QueryInterface(mOwnerContent);
     mChildProcess->SetOwnerElement(element);
@@ -1556,6 +1558,8 @@ nsFrameLoader::TryNewProcess()
     nsCOMPtr<nsIBrowserDOMWindow> browserDOMWin;
     rootChromeWin->GetBrowserDOMWindow(getter_AddRefs(browserDOMWin));
     mChildProcess->SetBrowserDOMWindow(browserDOMWin);
+    
+    mChildHost = parent;
   }
   return true;
 }

content/base/src/nsFrameLoader.h

@@ -190,6 +190,7 @@ private:
   PRPackedBool mRemoteWidgetCreated : 1;
   bool mRemoteFrame;
   // XXX leaking
+  nsCOMPtr<nsIObserver> mChildHost;
   mozilla::dom::TabParent* mChildProcess;
 
 #ifdef MOZ_WIDGET_GTK2

dom/ipc/ContentProcessParent.cpp

@@ -54,10 +54,6 @@ using namespace mozilla::ipc;
 using namespace mozilla::net;
 using mozilla::MonitorAutoEnter;
 
-namespace {
-PRBool gSingletonDied = PR_FALSE;
-}
-
 namespace mozilla {
 namespace dom {
 
@@ -66,7 +62,10 @@ ContentProcessParent* ContentProcessParent::gSingleton;
 ContentProcessParent*
 ContentProcessParent::GetSingleton()
 {
-    if (!gSingleton && !gSingletonDied) {
+    if (gSingleton && !gSingleton->IsAlive())
+        gSingleton = nsnull;
+    
+    if (!gSingleton) {
         nsRefPtr<ContentProcessParent> parent = new ContentProcessParent();
         if (parent) {
             nsCOMPtr<nsIObserverService> obs =
@@ -103,6 +102,8 @@ ContentProcessParent::ActorDestroy(ActorDestroyReason why)
         threadInt->SetObserver(mOldObserver);
     if (mRunToCompletionDepth)
         mRunToCompletionDepth = 0;
+
+    mIsAlive = false;
 }
 
 TabParent*
@@ -127,6 +128,7 @@ ContentProcessParent::ContentProcessParent()
     : mMonitor("ContentProcessParent::mMonitor")
     , mRunToCompletionDepth(0)
     , mShouldCallUnblockChild(false)
+    , mIsAlive(true)
 {
     NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");
     mSubprocess = new GeckoChildProcessHost(GeckoProcessType_Content);
@@ -142,11 +144,18 @@ ContentProcessParent::ContentProcessParent()
 ContentProcessParent::~ContentProcessParent()
 {
     NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");
-    NS_ASSERTION(gSingleton == this, "More than one singleton?!");
-    gSingletonDied = PR_TRUE;
+    //If the previous content process has died, a new one could have
+    //been started since.
+    if (gSingleton == this)
         gSingleton = nsnull;
 }
 
+bool
+ContentProcessParent::IsAlive()
+{
+    return mIsAlive;
+}
+
 NS_IMPL_THREADSAFE_ISUPPORTS2(ContentProcessParent,
                               nsIObserver,
                               nsIThreadObserver)

dom/ipc/ContentProcessParent.h

@@ -86,6 +86,8 @@ public:
     void ReportChildAlreadyBlocked();
     bool RequestRunToCompletion();
 
+    bool IsAlive();
+
 protected:
     virtual void ActorDestroy(ActorDestroyReason why);
 
@@ -117,6 +119,7 @@ private:
     bool mShouldCallUnblockChild;
     nsCOMPtr<nsIThreadObserver> mOldObserver;
 
+    bool mIsAlive;
 };
 
 } // namespace dom