Adds trace events from tests run in Java on the device to trace output file.

Creates new TestTraceEvent.java class, with some of the functionality of the old (unused) PerfTraceEvent.

This is used within the JUnit4 test runner to track tests, and added by the Python test runner code to its trace output.

Bug: 
Change-Id: Ie0b6c180a4c7f77a13e1bd08a4e641cc1a3db3ef
Reviewed-on: https://chromium-review.googlesource.com/578707
Reviewed-by: Michael Case <mikecase@chromium.org>
Reviewed-by: Tommy Nyquist <nyquist@chromium.org>
Commit-Queue: Nick Ward <npward@google.com>
Cr-Original-Commit-Position: refs/heads/master@{#493465}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 85689988f176cc19c6274416b9fe45b284397ba1

android/pylib/local/device/local_device_instrumentation_test_run.py

@@ -3,6 +3,7 @@
 # found in the LICENSE file.
 
 import contextlib
+import hashlib
 import json
 import logging
 import os
@@ -30,6 +31,7 @@ from pylib.utils import instrumentation_tracing
 from pylib.utils import logdog_helper
 from pylib.utils import shared_preference_utils
 from py_trace_event import trace_event
+from py_trace_event import trace_time
 from py_utils import contextlib_ext
 from py_utils import tempfile_ext
 import tombstones
@@ -65,6 +67,8 @@ EXTRA_SCREENSHOT_FILE = (
 EXTRA_UI_CAPTURE_DIR = (
     'org.chromium.base.test.util.Screenshooter.ScreenshotDir')
 
+EXTRA_TRACE_FILE = ('org.chromium.base.test.BaseJUnit4ClassRunner.TraceFile')
+
 _EXTRA_TEST_LIST = (
     'org.chromium.base.test.BaseChromiumAndroidJUnitRunner.TestList')
 
@@ -353,6 +357,11 @@ class LocalDeviceInstrumentationTestRun(
 
     extras[EXTRA_UI_CAPTURE_DIR] = self._ui_capture_dir[device]
 
+    if self._env.trace_output:
+      trace_device_file = device_temp_file.DeviceTempFile(
+          device.adb, suffix='.json', dir=device.GetExternalStoragePath())
+      extras[EXTRA_TRACE_FILE] = trace_device_file.name
+
     if isinstance(test, list):
       if not self._test_instance.driver_apk:
         raise Exception('driver_apk does not exist. '
@@ -436,6 +445,9 @@ class LocalDeviceInstrumentationTestRun(
     logcat_url = logmon.GetLogcatURL()
     duration_ms = time_ms() - start_ms
 
+    if self._env.trace_output:
+      self._SaveTraceData(trace_device_file, device, test['class'])
+
     # TODO(jbudorick): Make instrumentation tests output a JSON so this
     # doesn't have to parse the output.
     result_code, result_bundle, statuses = (
@@ -607,6 +619,65 @@ class LocalDeviceInstrumentationTestRun(
         pickle_path, test_apk_path, raw_tests)
     return raw_tests
 
+  def _SaveTraceData(self, trace_device_file, device, test_class):
+    trace_host_file = self._env.trace_output
+
+    if device.FileExists(trace_device_file.name):
+      try:
+        java_trace_json = device.ReadFile(trace_device_file.name)
+      except IOError:
+        raise Exception('error pulling trace file from device')
+      finally:
+        trace_device_file.close()
+
+      process_name = '%s (device %s)' % (test_class, device.serial)
+      process_hash = int(hashlib.md5(process_name).hexdigest()[:6], 16)
+
+      java_trace = json.loads(java_trace_json)
+      java_trace.sort(key=lambda event: event['ts'])
+
+      get_date_command = 'echo $EPOCHREALTIME'
+      device_time = device.RunShellCommand(get_date_command, single_line=True)
+      device_time = float(device_time) * 1e6
+      system_time = trace_time.Now()
+      time_difference = system_time - device_time
+
+      threads_to_add = set()
+      for event in java_trace:
+        # Ensure thread ID and thread name will be linked in the metadata.
+        threads_to_add.add((event['tid'], event['name']))
+
+        event['pid'] = process_hash
+
+        # Adjust time stamp to align with Python trace times (from
+        # trace_time.Now()).
+        event['ts'] += time_difference
+
+      for tid, thread_name in threads_to_add:
+        thread_name_metadata = {'pid': process_hash, 'tid': tid,
+                                'ts': 0, 'ph': 'M', 'cat': '__metadata',
+                                'name': 'thread_name',
+                                'args': {'name': thread_name}}
+        java_trace.append(thread_name_metadata)
+
+      process_name_metadata = {'pid': process_hash, 'tid': 0, 'ts': 0,
+                               'ph': 'M', 'cat': '__metadata',
+                               'name': 'process_name',
+                               'args': {'name': process_name}}
+      java_trace.append(process_name_metadata)
+
+      java_trace_json = json.dumps(java_trace)
+      java_trace_json = java_trace_json.rstrip(' ]')
+
+      with open(trace_host_file, 'r') as host_handle:
+        host_contents = host_handle.readline()
+
+      if host_contents:
+        java_trace_json = ',%s' % java_trace_json.lstrip(' [')
+
+      with open(trace_host_file, 'a') as host_handle:
+        host_handle.write(java_trace_json)
+
   def _SaveScreenshot(self, device, screenshot_host_dir, screenshot_device_file,
                       test_name, results):
     if screenshot_host_dir: