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diff --git a/gfx/layers/client/CompositableClient.h b/gfx/layers/client/CompositableClient.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef MOZILLA_GFX_BUFFERCLIENT_H
+#define MOZILLA_GFX_BUFFERCLIENT_H
+
+#include <stdint.h>  // for uint64_t
+
+#include <map>     // for map
+#include <vector>  // for vector
+
+#include "mozilla/Assertions.h"  // for MOZ_CRASH
+#include "mozilla/DataMutex.h"
+#include "mozilla/RefPtr.h"     // for already_AddRefed, RefCounted
+#include "mozilla/gfx/Types.h"  // for SurfaceFormat
+#include "mozilla/layers/CompositorTypes.h"
+#include "mozilla/layers/LayersTypes.h"    // for LayersBackend, TextureDumpMode
+#include "mozilla/layers/TextureClient.h"  // for TextureClient
+#include "mozilla/webrender/WebRenderTypes.h"  // for RenderRoot
+#include "nsISupportsImpl.h"                   // for MOZ_COUNT_CTOR, etc
+
+namespace mozilla {
+namespace layers {
+
+class CompositableClient;
+class ImageBridgeChild;
+class ImageContainer;
+class CompositableForwarder;
+class CompositableChild;
+class TextureClientRecycleAllocator;
+class ContentClientRemoteBuffer;
+
+/**
+ * CompositableClient manages the texture-specific logic for composite layers,
+ * independently of the layer. It is the content side of a CompositableClient/
+ * CompositableHost pair.
+ *
+ * CompositableClient's purpose is to send texture data to the compositor side
+ * along with any extra information about how the texture is to be composited.
+ * Things like opacity or transformation belong to layer and not compositable.
+ *
+ * Since Compositables are independent of layers it is possible to create one,
+ * connect it to the compositor side, and start sending images to it. This alone
+ * is arguably not very useful, but it means that as long as a shadow layer can
+ * do the proper magic to find a reference to the right CompositableHost on the
+ * Compositor side, a Compositable client can be used outside of the main
+ * shadow layer forwarder machinery that is used on the main thread.
+ *
+ * The first step is to create a Compositable client and call Connect().
+ * Connect() creates the underlying IPDL actor (see CompositableChild) and the
+ * corresponding CompositableHost on the other side.
+ *
+ * To do async texture transfer (like async-video), the CompositableClient
+ * should be created with a different CompositableForwarder (like
+ * ImageBridgeChild) and attachment is done with
+ * CompositableForwarder::AttachAsyncCompositable that takes an identifier
+ * instead of a CompositableChild, since the CompositableClient is not managed
+ * by this layer forwarder (the matching uses a global map on the compositor
+ * side, see CompositableMap in ImageBridgeParent.cpp)
+ *
+ * Subclasses: Painted layers use ContentClients, ImageLayers use ImageClients,
+ * Canvas layers use CanvasClients (but ImageHosts). We have a different
+ * subclass where we have a different way of interfacing with the textures - in
+ * terms of drawing into the compositable and/or passing its contents to the
+ * compostior.
+ */
+class CompositableClient {
+ protected:
+  virtual ~CompositableClient();
+
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(CompositableClient)
+
+  explicit CompositableClient(CompositableForwarder* aForwarder,
+                              TextureFlags aFlags = TextureFlags::NO_FLAGS);
+
+  virtual void Dump(std::stringstream& aStream, const char* aPrefix = "",
+                    bool aDumpHtml = false,
+                    TextureDumpMode aCompress = TextureDumpMode::Compress){};
+
+  virtual TextureInfo GetTextureInfo() const = 0;
+
+  LayersBackend GetCompositorBackendType() const;
+
+  already_AddRefed<TextureClient> CreateBufferTextureClient(
+      gfx::SurfaceFormat aFormat, gfx::IntSize aSize,
+      gfx::BackendType aMoz2dBackend = gfx::BackendType::NONE,
+      TextureFlags aFlags = TextureFlags::DEFAULT);
+
+  already_AddRefed<TextureClient> CreateTextureClientForDrawing(
+      gfx::SurfaceFormat aFormat, gfx::IntSize aSize, BackendSelector aSelector,
+      TextureFlags aTextureFlags,
+      TextureAllocationFlags aAllocFlags = ALLOC_DEFAULT);
+
+  /**
+   * Establishes the connection with compositor side through IPDL
+   */
+  virtual bool Connect(ImageContainer* aImageContainer = nullptr);
+
+  void Destroy();
+
+  bool IsConnected() const;
+
+  CompositableForwarder* GetForwarder() const { return mForwarder; }
+
+  /**
+   * This identifier is what lets us attach async compositables with a shadow
+   * layer. It is not used if the compositable is used with the regular shadow
+   * layer forwarder.
+   *
+   * If this returns empty, it means the compositable is not async (it is used
+   * on the main thread).
+   */
+  CompositableHandle GetAsyncHandle() const;
+
+  /**
+   * Handle for IPDL communication.
+   */
+  CompositableHandle GetIPCHandle() const { return mHandle; }
+
+  /**
+   * Tells the Compositor to create a TextureHost for this TextureClient.
+   */
+  virtual bool AddTextureClient(TextureClient* aClient);
+
+  /**
+   * A hook for the when the Compositable is detached from it's layer.
+   */
+  virtual void OnDetach() {}
+
+  /**
+   * Clear any resources that are not immediately necessary. This may be called
+   * in low-memory conditions.
+   */
+  virtual void ClearCachedResources();
+
+  /**
+   * Shrink memory usage.
+   * Called when "memory-pressure" is observed.
+   */
+  virtual void HandleMemoryPressure();
+
+  /**
+   * Should be called when deataching a TextureClient from a Compositable,
+   * because some platforms need to do some extra book keeping when this
+   * happens.
+   *
+   * See AutoRemoveTexture to automatically invoke this at the end of a scope.
+   */
+  virtual void RemoveTexture(TextureClient* aTexture);
+
+  void InitIPDL(const CompositableHandle& aHandle);
+
+  TextureFlags GetTextureFlags() const { return mTextureFlags; }
+
+  TextureClientRecycleAllocator* GetTextureClientRecycler();
+
+  bool HasTextureClientRecycler() {
+    auto lock = mTextureClientRecycler.Lock();
+    return !!(*lock);
+  }
+
+  static void DumpTextureClient(std::stringstream& aStream,
+                                TextureClient* aTexture,
+                                TextureDumpMode aCompress);
+
+ protected:
+  RefPtr<CompositableForwarder> mForwarder;
+  // Some layers may want to enforce some flags to all their textures
+  // (like disallowing tiling)
+  Atomic<TextureFlags> mTextureFlags;
+  DataMutex<RefPtr<TextureClientRecycleAllocator>> mTextureClientRecycler;
+
+  // Only ever accessed via mTextureClientRecycler's Lock
+  CompositableHandle mHandle;
+  bool mIsAsync;
+
+  friend class CompositableChild;
+};
+
+/**
+ * Helper to call RemoveTexture at the end of a scope.
+ */
+struct AutoRemoveTexture {
+  explicit AutoRemoveTexture(CompositableClient* aCompositable,
+                             TextureClient* aTexture = nullptr)
+      : mTexture(aTexture), mCompositable(aCompositable) {}
+
+  ~AutoRemoveTexture();
+
+  RefPtr<TextureClient> mTexture;
+
+ private:
+  CompositableClient* mCompositable;
+};
+
+}  // namespace layers
+}  // namespace mozilla
+
+#endif