pw_watch: Fix startup exception

A past CL (108730) introduced a better log rendering timer but
forgot to add that functionality to pw watch --fullscreen

Change-Id: I427909acb07e47f220640d6e5ff93c3060030d90
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/109713
Pigweed-Auto-Submit: Anthony DiGirolamo <tonymd@google.com>
Reviewed-by: Wyatt Hepler <hepler@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>

pw_watch/py/pw_watch/watch_app.py

@@ -19,6 +19,7 @@
 from pathlib import Path
 import re
 import sys
+import time
 from typing import List, NoReturn, Optional
 
 from prompt_toolkit.application import Application
@@ -109,6 +110,9 @@ def __init__(self,
         self._build_error_count = 0
         self._errors_in_output = False
 
+        self.log_ui_update_frequency = 0.1  # 10 FPS
+        self._last_ui_update_time = time.time()
+
         self.ninja_log_pane = LogPane(application=self,
                                       pane_title='Pigweed Watch')
         self.ninja_log_pane.add_log_handler(_NINJA_LOG, level_name='INFO')
@@ -255,6 +259,16 @@ def _quit_with_confirm(_event):
             plugin_logger_name='pw_watch_stdout_checker',
         )
 
+    def logs_redraw(self):
+        emit_time = time.time()
+        # Has enough time passed since last UI redraw due to new logs?
+        if emit_time > self._last_ui_update_time + self.log_ui_update_frequency:
+            # Update last log time
+            self._last_ui_update_time = emit_time
+
+            # Trigger Prompt Toolkit UI redraw.
+            self.redraw_ui()
+
     def jump_to_error(self, backwards: bool = False) -> None:
         if not self.ninja_log_pane.log_view.search_text:
             self.ninja_log_pane.log_view.set_search_regex(