From 3a7f9cf922b038cbb038c340931e0e5cc9333784 Mon Sep 17 00:00:00 2001
From: Olli Pettay <Olli.Pettay@helsinki.fi>
Date: Wed, 28 Nov 2012 01:54:15 +0200
Subject: [PATCH] Bug 811206, Fix JSHolder drop handling, part 1 (base),
 r=mccr8

--HG--
extra : rebase_source : 0ea98d9e542ebade36653661fe4e941a03b87781
---
 content/base/src/nsContentUtils.cpp | 18 ++----------------
 js/xpconnect/src/XPCJSRuntime.cpp   |  8 ++++++++
 2 files changed, 10 insertions(+), 16 deletions(-)

diff --git a/content/base/src/nsContentUtils.cpp b/content/base/src/nsContentUtils.cpp
index f8109bd64d6..9587fb99fdb 100644
--- a/content/base/src/nsContentUtils.cpp
+++ b/content/base/src/nsContentUtils.cpp
@@ -4519,28 +4519,14 @@ nsContentUtils::HoldJSObjects(void* aScriptObjectHolder,
 {
   NS_ENSURE_TRUE(sXPConnect, NS_ERROR_UNEXPECTED);
 
-  nsresult rv = sXPConnect->AddJSHolder(aScriptObjectHolder, aTracer);
-  NS_ENSURE_SUCCESS(rv, rv);
-
-  if (sJSGCThingRootCount++ == 0) {
-    nsLayoutStatics::AddRef();
-  }
-  NS_LOG_ADDREF(sXPConnect, sJSGCThingRootCount, "HoldJSObjects",
-                sizeof(void*));
-
-  return NS_OK;
+  return sXPConnect->AddJSHolder(aScriptObjectHolder, aTracer);
 }
 
 /* static */
 nsresult
 nsContentUtils::DropJSObjects(void* aScriptObjectHolder)
 {
-  NS_LOG_RELEASE(sXPConnect, sJSGCThingRootCount - 1, "HoldJSObjects");
-  nsresult rv = sXPConnect->RemoveJSHolder(aScriptObjectHolder);
-  if (--sJSGCThingRootCount == 0) {
-    nsLayoutStatics::Release();
-  }
-  return rv;
+  return sXPConnect->RemoveJSHolder(aScriptObjectHolder);
 }
 
 #ifdef DEBUG
diff --git a/js/xpconnect/src/XPCJSRuntime.cpp b/js/xpconnect/src/XPCJSRuntime.cpp
index 1bb006b091a..aadfccb91b5 100644
--- a/js/xpconnect/src/XPCJSRuntime.cpp
+++ b/js/xpconnect/src/XPCJSRuntime.cpp
@@ -250,7 +250,11 @@ nsresult
 XPCJSRuntime::AddJSHolder(void* aHolder, nsScriptObjectTracer* aTracer)
 {
     MOZ_ASSERT(aTracer->Trace, "AddJSHolder needs a non-null Trace function");
+    bool wasEmpty = mJSHolders.Count() == 0;
     mJSHolders.Put(aHolder, aTracer);
+    if (wasEmpty && mJSHolders.Count() == 1) {
+      nsLayoutStatics::AddRef();
+    }
 
     return NS_OK;
 }
@@ -258,7 +262,11 @@ XPCJSRuntime::AddJSHolder(void* aHolder, nsScriptObjectTracer* aTracer)
 nsresult
 XPCJSRuntime::RemoveJSHolder(void* aHolder)
 {
+    bool hadOne = mJSHolders.Count() == 1;
     mJSHolders.Remove(aHolder);
+    if (hadOne && mJSHolders.Count() == 0) {
+      nsLayoutStatics::Release();
+    }
 
     return NS_OK;
 }