[Mojo Video Capture] Simplify media::VideoCaptureDevice::Client:Buffer to a struct

media/capture/video/video_capture_buffer_pool.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 MEDIA_CAPTURE_VIDEO_VIDEO_CAPTURE_BUFFER_POOL_H_
 #define MEDIA_CAPTURE_VIDEO_VIDEO_CAPTURE_BUFFER_POOL_H_
 
 #include "base/memory/ref_counted.h"
 #include "media/capture/capture_export.h"
 #include "media/capture/video_capture_types.h"
@@ skipping 26 matching lines @@
 // reallocated at larger size. When reallocation occurs, new buffer IDs will
 // circulate.
 class CAPTURE_EXPORT VideoCaptureBufferPool
     : public base::RefCountedThreadSafe<VideoCaptureBufferPool> {
  public:
   static constexpr int kInvalidId = -1;
 
   // One-time (per client/per-buffer) call to allow sharing |buffer_id|.
   virtual mojo::ScopedSharedBufferHandle GetHandleForTransit(int buffer_id) = 0;
 
-  // Try and obtain a BufferHandle for |buffer_id|.
-  virtual std::unique_ptr<VideoCaptureBufferHandle> GetBufferHandle(
+  // Try and obtain a read/write access to the buffer.
+  virtual std::unique_ptr<VideoCaptureBufferHandle> GetReadWriteAccess(
       int buffer_id) = 0;
 
   // Reserve or allocate a buffer to support a packed frame of |dimensions| of
   // pixel |format| and return its id. This will fail (returning kInvalidId) if
   // the pool already is at its |count| limit of the number of allocations, and
   // all allocated buffers are in use by the producer and/or consumers.
   //
   // If successful, the reserved buffer remains reserved (and writable by the
   // producer) until ownership is transferred either to the consumer via
   // HoldForConsumers(), or back to the pool with
@@ skipping 42 matching lines @@
  protected:
   virtual ~VideoCaptureBufferPool() {}
 
  private:
   friend class base::RefCountedThreadSafe<VideoCaptureBufferPool>;
 };
 
 }  // namespace media
 
 #endif  // MEDIA_CAPTURE_VIDEO_VIDEO_CAPTURE_BUFFER_POOL_H_