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

scripts/slave/recipes/android_webview_cts_tests.py

Index: scripts/slave/recipes/android_webview_cts_tests.py
diff --git a/scripts/slave/recipes/android_webview_cts_tests.py b/scripts/slave/recipes/android_webview_cts_tests.py
index 7155a2374bb3a5d91fb41a29fa376e65b785bf7c..a0909dbe00f670c029e054bf735d42e15ae8ea69 100644
--- a/scripts/slave/recipes/android_webview_cts_tests.py
+++ b/scripts/slave/recipes/android_webview_cts_tests.py
@@ -117,8 +117,9 @@ def RunSteps(api):
       if failed_method.get('name') not in EXPECTED_FAILURE[failed_class_name]:
         api.step.active_result.presentation.status = api.step.FAILURE
 
-  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)
   api.chromium_android.test_report()
 
 def GenTests(api):