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

media/capture/video/video_capture_buffer_pool.h

Index: media/capture/video/video_capture_buffer_pool.h
diff --git a/media/capture/video/video_capture_buffer_pool.h b/media/capture/video/video_capture_buffer_pool.h
index 9829a0aa13e4568dbdc048793a519efb69464138..2d049570f95fa2d2868de33b86b4d5661d3fef4d 100644
--- a/media/capture/video/video_capture_buffer_pool.h
+++ b/media/capture/video/video_capture_buffer_pool.h
@@ -42,11 +42,10 @@
   static constexpr int kInvalidId = -1;
 
   // One-time (per client/per-buffer) call to allow sharing |buffer_id|.
-  virtual mojo::ScopedSharedBufferHandle GetHandleForInterProcessTransit(
-      int buffer_id) = 0;
+  virtual mojo::ScopedSharedBufferHandle GetHandleForTransit(int buffer_id) = 0;
 
-  // Try and obtain a read/write access to the buffer.
-  virtual std::unique_ptr<VideoCaptureBufferHandle> GetHandleForInProcessAccess(
+  // Try and obtain a BufferHandle for |buffer_id|.
+  virtual std::unique_ptr<VideoCaptureBufferHandle> GetBufferHandle(
       int buffer_id) = 0;
 
   // Reserve or allocate a buffer to support a packed frame of |dimensions| of