camera_device: Remove private scope of Camera3RequestDescriptor

Camera3RequestDescriptor is a utility structure that groups information
about a capture request. It can be and will be extended to preserve the
context of a capture overall. Since the context of a capture needs to
be shared among other classes (for e.g. CameraStream) having a private
definition of the struct in CameraDevice class doesn't help.

Hence, de-scope the structure so that it can be shared with other
components (through references or pointers). Splitting the structure to
a separate file will help avoiding circular dependencies when using it
through the HAL implementation.

Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Hirokazu Honda <hiroh@chromium.org>

src/android/meson.build

@@ -45,6 +45,7 @@ android_hal_sources = files([
     'camera_hal_manager.cpp',
     'camera_metadata.cpp',
     'camera_ops.cpp',
+    'camera_request.cpp',
     'camera_stream.cpp',
     'camera_worker.cpp',
     'jpeg/encoder_libjpeg.cpp',