[Android] Generate html file for test runner trace instead of json.

build/android/pylib/local/device/local_device_test_run.py

Index: build/android/pylib/local/device/local_device_test_run.py
diff --git a/build/android/pylib/local/device/local_device_test_run.py b/build/android/pylib/local/device/local_device_test_run.py
index 1d7ebdf802802258f1c5d275e0b60b69913db8f2..c754a3d4a08a3b89caf196e9c1d12c8fdf16e65a 100644
--- a/build/android/pylib/local/device/local_device_test_run.py
+++ b/build/android/pylib/local/device/local_device_test_run.py
@@ -16,6 +16,7 @@ from pylib.base import base_test_result
 from pylib.base import test_run
 from pylib.base import test_collection
 from pylib.local.device import local_device_environment
+from tracing_build import trace2html
 
 
 _SIGTERM_TEST_LOG = (
@@ -203,6 +204,13 @@ class LocalDeviceTestRun(test_run.TestRun):
   def _ShouldShard(self):
     raise NotImplementedError
 
+  @staticmethod
+  def _JsonToTrace(json_path, html_path):
+    # First argument is call site.
+    cmd = [__file__, json_path, '--title', 'Android Test Runner Trace',
+           '--output', html_path]
+    trace2html.Main(cmd)
+
 
 class NoTestsError(Exception):
   """Error for when no tests are found."""