[Android] Add timeout for joining logcat record thread.

Currently, the logcat monitor can hang if nothing is being output
by logcat after you try to join the recorder thread. Adding a
timeout to join to prevent this.

BUG=581352

Review URL: https://codereview.chromium.org/1648443002

Cr-Commit-Position: refs/heads/master@{#371880}

build/android/devil/android/logcat_monitor.py

@@ -21,6 +21,7 @@ from devil.utils import reraiser_thread
 
 class LogcatMonitor(object):
 
+  _RECORD_THREAD_JOIN_WAIT = 2.0
   _WAIT_TIME = 0.2
   _THREADTIME_RE_FORMAT = (
       r'(?P<date>\S*) +(?P<time>\S*) +(?P<proc_id>%s) +(?P<thread_id>%s) +'
@@ -43,6 +44,7 @@ class LogcatMonitor(object):
     self._filter_specs = filter_specs
     self._output_file = output_file
     self._record_file = None
+    self._record_file_lock = threading.Lock()
     self._record_thread = None
     self._stop_recording_event = threading.Event()
 
@@ -155,13 +157,13 @@ class LogcatMonitor(object):
     def record_to_file():
       # Write the log with line buffering so the consumer sees each individual
       # line.
-      with open(self._record_file.name, 'a', 1) as f:
       for data in self._adb.Logcat(filter_specs=self._filter_specs,
                                    logcat_format='threadtime'):
+        with self._record_file_lock:
           if self._stop_recording_event.isSet():
-            f.flush()
             return
-          f.write(data + '\n')
+          if self._record_file and not self._record_file.closed:
+            self._record_file.write(data + '\n')
 
     self._stop_recording_event.clear()
     if not self._record_thread:
@@ -172,7 +174,7 @@ class LogcatMonitor(object):
     """Finish recording logcat."""
     if self._record_thread:
       self._stop_recording_event.set()
-      self._record_thread.join()
+      self._record_thread.join(timeout=self._RECORD_THREAD_JOIN_WAIT)
       self._record_thread.ReraiseIfException()
       self._record_thread = None
 
@@ -184,7 +186,7 @@ class LogcatMonitor(object):
     if self._clear:
       self._adb.Logcat(clear=True)
     if not self._record_file:
-      self._record_file = tempfile.NamedTemporaryFile()
+      self._record_file = tempfile.NamedTemporaryFile(mode='a', bufsize=1)
     self._StartRecording()
 
   def Stop(self):
@@ -194,6 +196,7 @@ class LogcatMonitor(object):
     |self._output_file|.
     """
     self._StopRecording()
+    with self._record_file_lock:
       if self._record_file and self._output_file:
         try:
           os.makedirs(os.path.dirname(self._output_file))
@@ -207,6 +210,7 @@ class LogcatMonitor(object):
 
     Should be called when finished using the logcat monitor.
     """
+    with self._record_file_lock:
       if self._record_file:
         self._record_file.close()
         self._record_file = None
@@ -222,10 +226,13 @@ class LogcatMonitor(object):
 
   def __del__(self):
     """Closes logcat recording file in case |Close| was never called."""
+    with self._record_file_lock:
       if self._record_file:
-      logging.warning('Need to call |Close| on the logcat monitor when done!')
+        logging.warning(
+            'Need to call |Close| on the logcat monitor when done!')
         self._record_file.close()
 
+
 class LogcatMonitorCommandError(device_errors.CommandFailedError):
   """Exception for errors with logcat monitor commands."""
   pass