exo: Recreate Surface resources on context lost.

components/exo/buffer.h

 // 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.
 
 #ifndef COMPONENTS_EXO_BUFFER_H_
 #define COMPONENTS_EXO_BUFFER_H_
 
 #include <memory>
 
 #include "base/callback.h"
@@ skipping 44 matching lines @@
 
   // This function can be used to acquire a texture mailbox for the contents of
   // buffer. Returns a release callback on success. The release callback should
   // be called before a new texture mailbox can be acquired unless
   // |non_client_usage| is true.
   std::unique_ptr<cc::SingleReleaseCallback> ProduceTextureMailbox(
       cc::TextureMailbox* mailbox,
       bool secure_output_only,
       bool client_usage);
 
+  // This should be called when the buffer is attached to a Surface.
+  void OnAttach() { ++attach_count_; }

[reveman, 2016/06/23 00:44:38]

Can you move this to .cc file and add a DLOG(WARNING) for when a buffer gets
attached to multiple surfaces as that's a result of bad behavior by the client?

+
+  // This should be called when the buffer is detached from a surface.
+  void OnDetach();
+
   // Returns the size of the buffer.
   gfx::Size GetSize() const;
 
   // Returns a trace value representing the state of the buffer.
   std::unique_ptr<base::trace_event::TracedValue> AsTracedValue() const;
 
  private:
   class Texture;
 
   // Decrements the use count of buffer and notifies the client that buffer
   // as been released if it reached 0.
   void Release();
 
+  // Runs the release callback if the buffer isn't attached or in use.
+  void CheckReleaseCallback();
+
   // This is used by ProduceTextureMailbox() to produce a release callback
   // that releases a texture so it can be destroyed or reused.
   void ReleaseTexture(std::unique_ptr<Texture> texture);
 
   // This is used by ProduceTextureMailbox() to produce a release callback
   // that releases the buffer contents referenced by a texture before the
   // texture is destroyed or reused.
   void ReleaseContentsTexture(std::unique_ptr<Texture> texture);
 
   // The GPU memory buffer that contains the contents of this buffer.
   std::unique_ptr<gfx::GpuMemoryBuffer> gpu_memory_buffer_;
 
   // Texture target that must be used when creating a texture for buffer.
   const unsigned texture_target_;
 
   // Query type that must be used when releasing buffer from a texture.
   const unsigned query_type_;
 
   // True if zero copy is used when producing a texture mailbox for buffer.
   const bool use_zero_copy_;
 
   // True if this buffer is an overlay candidate.
   const bool is_overlay_candidate_;
 
   // This is incremented when a texture mailbox is produced and decremented
   // when a texture mailbox is released. It is used to determine when we should
   // notify the client that buffer has been released.
   unsigned use_count_;
 
+  // This keeps track of how many Surfaces the buffer is attached to.
+  unsigned attach_count_ = 0;
+
   // The last used texture. ProduceTextureMailbox() will use this
   // instead of creating a new texture when possible.
   std::unique_ptr<Texture> texture_;
 
   // The last used contents texture. ProduceTextureMailbox() will use this
   // instead of creating a new texture when possible.
   std::unique_ptr<Texture> contents_texture_;
 
   // The client release callback.
   base::Closure release_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(Buffer);
 };
 
 }  // namespace exo
 
 #endif  // COMPONENTS_EXO_BUFFER_H_