Pepper takes ownership of a mailbox before passing it to the texture layer.

cc/layers/texture_layer.h

 // Copyright 2010 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_LAYERS_TEXTURE_LAYER_H_
 #define CC_LAYERS_TEXTURE_LAYER_H_
 
 #include <string>
 
 #include "base/callback.h"
@@ skipping 115 matching lines @@
 
   // Sets whether the texture should be blended with the background color
   // at draw time. Defaults to false.
   void SetBlendBackgroundColor(bool blend);
 
   // Code path for plugins which supply their own mailbox.
   void SetTextureMailbox(
       const TextureMailbox& mailbox,
       std::unique_ptr<SingleReleaseCallback> release_callback);
 
-  // Use this for special cases where the same texture is used to back the
-  // TextureLayer across all frames.
-  // WARNING: DON'T ACTUALLY USE THIS WHAT YOU ARE DOING IS WRONG.
-  // TODO(danakj): Remove this when pepper doesn't need it. crbug.com/350204
-  void SetTextureMailboxWithoutReleaseCallback(const TextureMailbox& mailbox);
-
   void SetNeedsDisplayRect(const gfx::Rect& dirty_rect) override;
 
   void SetLayerTreeHost(LayerTreeHost* layer_tree_host) override;
   bool Update() override;
   void PushPropertiesTo(LayerImpl* layer) override;
 
  protected:
   explicit TextureLayer(TextureLayerClient* client);
   ~TextureLayer() override;
   bool HasDrawableContent() const override;
@@ skipping 17 matching lines @@
   bool blend_background_color_;
 
   std::unique_ptr<TextureMailboxHolder::MainThreadReference> holder_ref_;
   bool needs_set_mailbox_;
 
   DISALLOW_COPY_AND_ASSIGN(TextureLayer);
 };
 
 }  // namespace cc
 #endif  // CC_LAYERS_TEXTURE_LAYER_H_