cc: Drop ContextProvider references on the impl thread before quitting

cc/resources/texture_mailbox_deleter.h

Index: cc/resources/texture_mailbox_deleter.h
diff --git a/cc/resources/texture_mailbox_deleter.h b/cc/resources/texture_mailbox_deleter.h
new file mode 100644
index 0000000000000000000000000000000000000000..608dd7a4ef7d7017aad60f2c4f00f48b9df52bb6
--- /dev/null
+++ b/cc/resources/texture_mailbox_deleter.h
@@ -0,0 +1,46 @@
+// Copyright 2013 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.
+
+#ifndef CC_RESOURCES_TEXTURE_MAILBOX_DELETER_H_
+#define CC_RESOURCES_TEXTURE_MAILBOX_DELETER_H_
+
+#include "base/memory/weak_ptr.h"
+#include "cc/base/cc_export.h"
+#include "cc/base/scoped_ptr_vector.h"
+#include "cc/resources/texture_mailbox.h"
+
+namespace cc {
+class ContextProvider;
+
+class CC_EXPORT TextureMailboxDeleter {
+ public:
+  TextureMailboxDeleter();
+  ~TextureMailboxDeleter();
+
+  // Returns a Callback that can be used as the ReleaseCallback for a
+  // TextureMailbox attached to the |texture_id|. The ReleaseCallback can
+  // be passed to other threads and will destroy the texture, once it is
+  // run, on the impl thread. If the TextureMailboxDeleter is destroyed
+  // due to the compositor shutting down, then the ReleaseCallback will
+  // become a no-op and the texture will be deleted immediately on the
+  // impl thread, along with dropping the reference to the ContextProvider.
+  TextureMailbox::ReleaseCallback GetReleaseCallback(
+      const scoped_refptr<ContextProvider>& context_provider,
+      unsigned texture_id);
+
+ private:
+  // Runs the |impl_callback| to delete the texture and removes the callback
+  // from the |impl_callbacks_| list.
+  void RunDeleteTextureOnImplThread(
+      TextureMailbox::ReleaseCallback* impl_callback,
+      unsigned sync_point,
+      bool is_lost);
+
+  base::WeakPtrFactory<TextureMailboxDeleter> weak_ptr_factory_;
+  ScopedPtrVector<TextureMailbox::ReleaseCallback> impl_callbacks_;
+};
+
+}  // namespace cc
+
+#endif  // CC_RESOURCES_TEXTURE_MAILBOX_DELETER_H_