Add ScopedSurfaceRequestManager

gpu/ipc/common/android/scoped_surface_request_manager.h

+// Copyright 2016 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 GPU_IPC_COMMON_ANDROID_SCOPED_SURFACE_REQUEST_MANAGER_H_
+#define GPU_IPC_COMMON_ANDROID_SCOPED_SURFACE_REQUEST_MANAGER_H_
+
+#include <stdint.h>
+
+#include "base/callback_forward.h"
+#include "gpu/gpu_export.h"
+
+namespace gl {
+class SurfaceTexture;
+class ScopedJavaSurface;
+}
+
+namespace gpu {
+
+// Defines an interface that allows the registration of gl::ScopedJavaSurface
+// requests in the browser process, and the forwarding of SurfaceTextures from
+// the GPU or the browser process to fulfill those requests at a later time.
+class GPU_EXPORT ScopedSurfaceRequestManager {

[watk, 2016/08/26 22:01:32]

I think it might be more understandable if you avoid a common interface for both
gpu and browser sides if they can't be used symmetrically. i.e., you can't use
this interface today without knowing which process you're in and which direction
the surfaces and requests are flowing.

Which means you can probably get rid of interfaces at all. Just have the
concrete browser side one. And something for the gpu side to fulfill requests. 
(maybe just a function/callback since it's only one call).

[tguilbert, 2016/08/29 18:30:46]

Updated. LMK if this is closer to what you had in mind.

[watk, 2016/08/29 19:42:25]

I like it!

+ public:
+  static ScopedSurfaceRequestManager* GetInstance();
+  static void SetInstance(ScopedSurfaceRequestManager* instance);
+
+  using ScopedSurfaceRequestCB = base::Callback<void(gl::ScopedJavaSurface)>;
+
+  // Registers |request_cb| for later retrieval.
+  // N.B: Should only be called in the browser process.
+  virtual void RegisterScopedSurfaceRequest(
+      uint64_t request_id,
+      ScopedSurfaceRequestCB request_cb) = 0;
+
+  // Unregisters and returns a ScopedSurfaceRequestCB previously registered
+  // using |request_id|.
+  // Returns a default ScopedSurfaceRequestCB() if there is no callback
+  // associated with |request_id|.
+  // N.B: Should only be called in the browser process.
+  virtual ScopedSurfaceRequestCB GetAndUnregisterScopedSurfaceRequest(
+      uint64_t request_id) = 0;
+
+  // Gets and unregisters the callback under |request_id|, and runs the callback
+  // with a gl:ScopedJavaSurface built from |surface_texture|.
+  // If |request_id| does not map to a request, nothing happens.
+  // N.B: Can be called from the GPU or the browser process.
+  virtual void FulfillScopedSurfaceRequest(
+      uint64_t request_id,
+      gl::SurfaceTexture* surface_texture) = 0;
+
+ protected:
+  virtual ~ScopedSurfaceRequestManager() {}
+};
+
+}  // namespace gpu
+
+#endif  // GPU_IPC_COMMON_ANDROID_SCOPED_SURFACE_REQUEST_MANAGER_H_