libcamera: Switch to FrameBuffer interface

Switch to the FrameBuffer interface where all buffers are treated as
external buffers and are allocated outside the camera. Applications
allocating buffers using libcamera are switched to use the
FrameBufferAllocator helper.

Follow-up changes to this one will finalize the transition to the new
FrameBuffer interface by removing code that is left unused after this
change.

Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

src/libcamera/include/pipeline_handler.h

@@ -21,12 +21,12 @@
 
 namespace libcamera {
 
-class Buffer;
 class Camera;
 class CameraConfiguration;
 class CameraManager;
 class DeviceEnumerator;
 class DeviceMatch;
+class FrameBuffer;
 class MediaDevice;
 class PipelineHandler;
 class Request;
@@ -85,7 +85,8 @@ public:
 
 	int queueRequest(Camera *camera, Request *request);
 
-	bool completeBuffer(Camera *camera, Request *request, Buffer *buffer);
+	bool completeBuffer(Camera *camera, Request *request,
+			    FrameBuffer *buffer);
 	void completeRequest(Camera *camera, Request *request);
 
 	const char *name() const { return name_; }