1 files changed, 58 insertions, 0 deletions
diff --git a/chromium/extensions/renderer/gc_callback.cc b/chromium/extensions/renderer/gc_callback.cc
new file mode 100644
index 00000000000..46b7f8acdf1
--- /dev/null
+++ b/chromium/extensions/renderer/gc_callback.cc
@@ -0,0 +1,58 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "extensions/renderer/gc_callback.h"
+
+#include "base/bind.h"
+#include "base/message_loop/message_loop.h"
+#include "extensions/renderer/script_context.h"
+
+namespace extensions {
+
+GCCallback::GCCallback(ScriptContext* context,
+                       const v8::Local<v8::Object>& object,
+                       const v8::Local<v8::Function>& callback,
+                       const base::Closure& fallback)
+    : context_(context),
+      object_(context->isolate(), object),
+      callback_(context->isolate(), callback),
+      fallback_(fallback),
+      weak_ptr_factory_(this) {
+  object_.SetWeak(this, OnObjectGC, v8::WeakCallbackType::kParameter);
+  context->AddInvalidationObserver(base::Bind(&GCCallback::OnContextInvalidated,
+                                              weak_ptr_factory_.GetWeakPtr()));
+}
+
+GCCallback::~GCCallback() {}
+
+// static
+void GCCallback::OnObjectGC(const v8::WeakCallbackInfo<GCCallback>& data) {
+  // Usually FirstWeakCallback should do nothing other than reset |object_|
+  // and then set a second weak callback to run later. We can sidestep that,
+  // because posting a task to the current message loop is all but free - but
+  // DO NOT add any more work to this method. The only acceptable place to add
+  // code is RunCallback.
+  GCCallback* self = data.GetParameter();
+  self->object_.Reset();
+  base::MessageLoop::current()->PostTask(
+      FROM_HERE, base::Bind(&GCCallback::RunCallback,
+                            self->weak_ptr_factory_.GetWeakPtr()));
+}
+
+void GCCallback::RunCallback() {
+  fallback_.Reset();
+  v8::Isolate* isolate = context_->isolate();
+  v8::HandleScope handle_scope(isolate);
+  context_->CallFunction(v8::Local<v8::Function>::New(isolate, callback_));
+  delete this;
+}
+
+void GCCallback::OnContextInvalidated() {
+  if (!fallback_.is_null()) {
+    fallback_.Run();
+    delete this;
+  }
+}
+
+}  // namespace extensions