TTS in the toolkit need initialize gstreamer - Fixes #4851

If is not initialized, the check for the espeak plugin will fail.
This patch also check for the espeak plugin at the beginnig
avoiding check every time the function enabled() is called.

src/sugar3/speech.py

@@ -18,7 +18,6 @@ import os
 import logging
 from gettext import gettext as _
 
-from gi.repository.GLib import GError
 from gi.repository import Gio
 from gi.repository import Gtk
 from gi.repository import Gdk
@@ -27,7 +26,10 @@ from gi.repository import GObject
 _HAS_GST = True
 try:
     from gi.repository import Gst
+    Gst.init(None)
+    Gst.parse_launch('espeak')
 except:
+    logging.error('Gst or the espeak plugin is not installed in the system.')
     _HAS_GST = False
 
 from sugar3 import power
@@ -116,24 +118,6 @@ translated_espeak_voices = {
 }
 
 
-def _has_espeak_module():
-    try:
-        Gst.parse_launch('espeak')
-    except GError:
-        logging.error('The speech plugin is not installed in the system.')
-        return False
-    return True
-
-
-def _check_modules():
-    if not _HAS_GST:
-        logging.error('GST is not installed in the system.')
-        return False
-    if not _has_espeak_module():
-        return False
-    return True
-
-
 class SpeechManager(GObject.GObject):
 
     __gtype_name__ = 'SpeechManager'
@@ -169,7 +153,7 @@ class SpeechManager(GObject.GObject):
         self.restore()
 
     def enabled(self):
-        return _check_modules()
+        return _HAS_GST
 
     def _update_state(self, player, signal):
         self._is_playing = (signal == 'play')
@@ -277,7 +261,6 @@ class _GstSpeechPlayer(GObject.GObject):
     }
 
     def __init__(self):
-        Gst.init(None)
         GObject.GObject.__init__(self)
         self._pipeline = None
         self._all_voices = None