libcamera: camera: Associate cameras with their pipeline handler

The PipelineHandler which creates a Camera is responsible for serving
any operation requested by the user. In order forward the public API
calls, the camera needs to store a reference to its pipeline handler.

Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
Changes since v1:

- Create pipeline handlers is shared pointers, make them inherit from
  std::enable_shared_from_this<> and stored them in shared pointers.

src/libcamera/pipeline/vimc.cpp

@@ -57,14 +57,7 @@ bool PipeHandlerVimc::match(DeviceEnumerator *enumerator)
 
 	dev_->acquire();
 
-	/*
-	 * NOTE: A more complete Camera implementation could
-	 * be passed the MediaDevice(s) it controls here or
-	 * a reference to the PipelineHandler. Which method
-	 * will be chosen depends on how the Camera
-	 * object is modeled.
-	 */
-	std::shared_ptr<Camera> camera = Camera::create("Dummy VIMC Camera");
+	std::shared_ptr<Camera> camera = Camera::create(this, "Dummy VIMC Camera");
 	manager_->addCamera(std::move(camera));
 
 	return true;