[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 8f74f894ac134a2f4a8ce9a8adee9c9cc29d9189..0f3e29a92ceced9bce4580788d00ca23a5d6a30c 100644
--- a/scripts/slave/recipes/android_webview_cts_tests.py
+++ b/scripts/slave/recipes/android_webview_cts_tests.py
@@ -125,8 +125,9 @@ def RunSteps(api):
             [['unexpected failures:', unexpected_test_failures],
              ['not executed:', not_executed_tests]]))
 
-  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()
 
   if unexpected_test_failures: