[pitivi] previewers: Make PreviewGeneratorManager Loggable

[Alexandru Băluț <alexbalut src gnome org>]

commit e667fdebefe8d08d6fcdd8468e796bc4a0113c24
Author: Alexandru Băluț <alexandru balut gmail com>
Date:   Sun Dec 10 20:08:50 2017 +0100

    previewers: Make PreviewGeneratorManager Loggable
    
    121fd44faae28901a86d4042bb47b38050753d20 assumes the
    PreviewGeneratorManager class extends Loggable.
    
    Also removed some unused fields.
    
    Reviewed-by: Thibault Saunier <tsaunier gnome org>
    Differential Revision: https://phabricator.freedesktop.org/D1910

 pitivi/timeline/previewers.py |    7 +++----
 1 files changed, 3 insertions(+), 4 deletions(-)
---
diff --git a/pitivi/timeline/previewers.py b/pitivi/timeline/previewers.py
index a657daa..ede626f 100644
--- a/pitivi/timeline/previewers.py
+++ b/pitivi/timeline/previewers.py
@@ -295,10 +295,12 @@ Gst.Element.register(None, "teedthumbnailbin", Gst.Rank.NONE,
 
 
 # pylint: disable=too-few-public-methods
-class PreviewGeneratorManager():
+class PreviewGeneratorManager(Loggable):
     """Manager for running the previewers."""
 
     def __init__(self):
+        Loggable.__init__(self)
+
         # The current Previewer per GES.TrackType.
         self._current_previewers = {}
         # The queue of Previewers.
@@ -419,7 +421,6 @@ class VideoPreviewer(Previewer, Zoomable, Loggable):
         Loggable.__init__(self)
 
         # Variables related to the timeline objects
-        self.timeline = ges_elem.get_parent().get_timeline().ui
         self.ges_elem = ges_elem
 
         # Guard against malformed URIs
@@ -431,7 +432,6 @@ class VideoPreviewer(Previewer, Zoomable, Loggable):
         self.wishlist = []
         self.queue = []
         self._thumb_cb_id = None
-        self._running = False
 
         # We should have one thumbnail per thumb_period.
         # TODO: get this from the user settings
@@ -903,7 +903,6 @@ class AudioPreviewer(Previewer, Zoomable, Loggable):
 
         self.discovered = False
         self.ges_elem = ges_elem
-        self.timeline = ges_elem.get_parent().get_timeline().ui
 
         asset = self.ges_elem.get_parent().get_asset()
         self.n_samples = asset.get_duration() / SAMPLE_DURATION