[Android] Add context manager to record logcat during step(s).

scripts/slave/recipe_modules/chromium_android/example.py

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 from recipe_engine.types import freeze
 
 DEPS = [
     'adb',
     'chromium',
     'chromium_android',
@@ skipping 144 matching lines @@
 
   try:
     if config.get('perf_config'):
       api.chromium_android.run_sharded_perf_tests(
           config='fake_config.json',
           flaky_config='flake_fakes.json',
           upload_archives_to_bucket='archives-bucket')
   except api.step.StepFailure as f:
     failure = f
 
-  api.chromium_android.run_instrumentation_suite(
-      name='AndroidWebViewTest',
-      apk_under_test=api.chromium_android.apk_path('AndroidWebView.apk'),
-      test_apk=api.chromium_android.apk_path('AndroidWebViewTest.apk'),
-      isolate_file_path='android_webview/android_webview_test_apk.isolate',
-      flakiness_dashboard='test-results.appspot.com',
-      annotation='SmallTest',
-      except_annotation='FlakyTest',
-      screenshot=True,
-      official_build=True,
-      host_driven_root=api.path['checkout'].join('chrome', 'test'))
-  api.chromium_android.run_test_suite(
-      'unittests',
-      isolate_file_path=api.path['checkout'].join('some_file.isolate'),
-      gtest_filter='WebRtc*',
-      tool='asan')
+  with api.chromium_android.logcat('AndroidWebViewTest'):
+    api.chromium_android.run_instrumentation_suite(
+        name='AndroidWebViewTest',
+        apk_under_test=api.chromium_android.apk_path('AndroidWebView.apk'),
+        test_apk=api.chromium_android.apk_path('AndroidWebViewTest.apk'),
+        isolate_file_path='android_webview/android_webview_test_apk.isolate',
+        flakiness_dashboard='test-results.appspot.com',
+        annotation='SmallTest',
+        except_annotation='FlakyTest',
+        screenshot=True,
+        official_build=True,
+        host_driven_root=api.path['checkout'].join('chrome', 'test'))
+  with api.chromium_android.logcat('unittests'):
+    api.chromium_android.run_test_suite(
+        'unittests',
+        isolate_file_path=api.path['checkout'].join('some_file.isolate'),
+        gtest_filter='WebRtc*',
+        tool='asan')
   if not failure:
       api.chromium_android.run_bisect_script(extra_src='test.py',
                                              path_to_config='test.py')
-  api.chromium_android.logcat_dump()
-  api.chromium_android.stack_tool_steps()
+
+  logcat_file = api.chromium.output_dir.join('full_logcat')
+  api.chromium_android.logcat_dump(output_logcat_file=logcat_file)
+  api.chromium_android.stack_tool_steps(logcat_file=logcat_file)
   if config.get('coverage', False):
     api.chromium_android.coverage_report()
 
   if failure:
     raise failure
 
 def GenTests(api):
   def properties_for(buildername):
     return api.properties.generic(
         buildername=buildername,
@@ skipping 31 matching lines @@
 
   yield (api.test('gerrit_refs') +
       api.properties.generic(
         buildername='gerrit_try_builder',
         slavename='testslave',
         repo_name='src/repo',
         patch_url='https://the.patch.url/the.patch',
         repo_url='svn://svn.chromium.org/chrome/trunk/src',
         revision='4f4b02f6b7fa20a3a25682c457bbc8ad589c8a00',
         internal=True, **({'event.patchSet.ref':'refs/changes/50/176150/1'})))