[PATCH 2/2] perf timechart: Initialize Textual attributes in constructors

[Leo Yan <leo.yan@arm.com>]

When Textual is unavailable, pylint cannot resolve the inherited
virtual_size and sub_title attributes, which triggers pylint warnings
and caused arm64 cross build failure:

  ************* Module ttimechart
  python/ttimechart.py:1086:8: W0201: Attribute 'virtual_size' defined outside __init__ (attribute-defined-outside-init)
  python/ttimechart.py:1422:12: W0201: Attribute 'sub_title' defined outside __init__ (attribute-defined-outside-init)
  python/ttimechart.py:1496:8: W0201: Attribute 'sub_title' defined outside __init__ (attribute-defined-outside-init)
  python/ttimechart.py:1510:8: W0201: Attribute 'sub_title' defined outside __init__ (attribute-defined-outside-init)

Initialize both attributes in their respective constructors. Use
Textual's default empty virtual size, with the actual geometry
computed when the timeline mounts or resizes.

Fixes: e7a72d691980 ("perf timechart: Add an interactive --tui mode")
Signed-off-by: Leo Yan <leo.yan@arm.com>
---
 tools/perf/python/ttimechart.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/perf/python/ttimechart.py b/tools/perf/python/ttimechart.py
index 34ecf84e68c1db7f542070dde608ac09d662a1b2..16d2bbbdd98b23d64ab42643db42686cad98f0f0 100755
--- a/tools/perf/python/ttimechart.py
+++ b/tools/perf/python/ttimechart.py
@@ -1065,6 +1065,7 @@ class TimelineView(ScrollView):
         self.can_focus = True
         self.data = data
         self.rows = rows
+        self.virtual_size = Size(0, 0)
         self.cache: Dict[int, List[Cell]] = {}
         self.cache_key: Tuple[float, float, int, Optional[ThemeColors]] = (0.0, 0.0, 0, None)
         self.label_style = Style()
@@ -1332,6 +1333,7 @@ class TimechartApp(App):
         """
         super().__init__()
         self.input_name = input_name
+        self.sub_title = input_name
         self.power_only = power_only
         self.tasks_only = tasks_only
         self.filters = filters

-- 
2.34.1