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

scripts/slave/recipes/chromium.expected/amp_split_recipe_instrumentation_trigger_failure.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/bot_update.py",
       "--master",
       "chromium.fyi",
       "--builder",
       "Android Tests (amp instrumentation test split)",
@@ skipping 251 matching lines @@
       "@@@STEP_LOG_LINE@python.inline@  subprocess.check_call([adb_path, '-s', device, 'wait-for-device'])@@@",
       "@@@STEP_LOG_LINE@python.inline@  print 'Finished rooting device %s' % (device)@@@",
       "@@@STEP_LOG_END@python.inline@@@"
     ]
   },
   {
     "cmd": [
       "[BUILD]/scripts/slave/daemonizer.py",
       "--",
       "[SLAVE_BUILD]/src/build/android/adb_logcat_monitor.py",
-      "[SLAVE_BUILD]/src/out/logcat"
+      "[SLAVE_BUILD]/src/out/logcat_dir"
     ],
     "cwd": "[SLAVE_BUILD]",
     "env": {
       "PATH": "[SLAVE_BUILD]/src/third_party/android_tools/sdk/platform-tools:[SLAVE_BUILD]/src/build/android:%(PATH)s"
     },
     "name": "spawn_logcat_monitor"
   },
   {
     "cmd": [
       "python",
@@ skipping 225 matching lines @@
     "cwd": "[SLAVE_BUILD]",
     "name": "[trigger] AndroidWebViewTest",
     "~followup_annotations": [
       "step returned non-zero exit code: 1",
       "@@@STEP_LOG_LINE@json.output (invalid)@null@@@",
       "@@@STEP_LOG_END@json.output (invalid)@@@",
       "@@@STEP_FAILURE@@@"
     ]
   },
   {
+    "cmd": [],
+    "cwd": "[SLAVE_BUILD]",
+    "name": "AndroidWebViewTest"
+  },
+  {
+    "cmd": [
+      "[BUILD]/scripts/slave/daemonizer.py",
+      "--",
+      "[SLAVE_BUILD]/src/build/android/adb_logcat_monitor.py",
+      "[TMP_BASE]/logcat_tmp_1"
+    ],
+    "cwd": "[SLAVE_BUILD]",
+    "env": {
+      "PATH": "[SLAVE_BUILD]/src/third_party/android_tools/sdk/platform-tools:[SLAVE_BUILD]/src/build/android:%(PATH)s"
+    },
+    "name": "AndroidWebViewTest.spawn_logcat_monitor",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
     "cmd": [
       "[SLAVE_BUILD]/src/build/android/adb_install_apk.py",
       "[SLAVE_BUILD]/src/out/Release/apks/AndroidWebView",
       "-v",
       "--blacklist-file",
       "[SLAVE_BUILD]/src/out/bad_devices.json",
       "--release"
     ],
     "cwd": "[SLAVE_BUILD]",
     "env": {
       "PATH": "[SLAVE_BUILD]/src/third_party/android_tools/sdk/platform-tools:[SLAVE_BUILD]/src/build/android:%(PATH)s"
     },
-    "name": "install AndroidWebView"
+    "name": "AndroidWebViewTest.install AndroidWebView",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
   },
   {
     "cmd": [
       "python",
       "-u",
       "[SLAVE_BUILD]/src/build/android/test_runner.py",
       "instrumentation",
       "--test-apk",
       "[SLAVE_BUILD]/src/out/Release/apks/AndroidWebViewTest",
       "--blacklist-file",
       "[SLAVE_BUILD]/src/out/bad_devices.json",
       "--apk-under-test",
       "[SLAVE_BUILD]/src/out/Release/apks/AndroidWebView",
       "--isolate-file-path",
       "[SLAVE_BUILD]/src/android_webview/android_webview_test_apk.isolate",
       "--flakiness-dashboard-server",
       "test-results.appspot.com",
       "--verbose",
       "--release",
       "--json-results-file",
       "/path/to/tmp/json"
     ],
     "cwd": "[SLAVE_BUILD]",
-    "name": "Instrumentation test AndroidWebViewTest",
+    "name": "AndroidWebViewTest.Instrumentation test AndroidWebViewTest",
     "~followup_annotations": [
-      "@@@STEP_TEXT@<br/>failures:<br/>TestB<br/>@@@"
+      "@@@STEP_NEST_LEVEL@1@@@"
     ]
   },
   {
+    "cmd": [
+      "python",
+      "-u",
+      "[BUILD]/scripts/slave/tee.py",
+      "/path/to/tmp/logcat",
+      "--",
+      "[SLAVE_BUILD]/src/build/android/adb_logcat_printer.py",
+      "[TMP_BASE]/logcat_tmp_1"
+    ],
+    "cwd": "[SLAVE_BUILD]",
+    "name": "AndroidWebViewTest.logcat_dump",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/daemonizer.py",
       "--action",
       "stop",
       "--pid-file-path",
       "/tmp/device_monitor.pid"
     ],
     "cwd": "[SLAVE_BUILD]",
     "name": "shutdown_device_monitor"
   },
   {
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/tee.py",
       "[SLAVE_BUILD]/src/out/Release/full_log",
       "--",
       "[SLAVE_BUILD]/src/build/android/adb_logcat_printer.py",
-      "[SLAVE_BUILD]/src/out/logcat"
+      "[SLAVE_BUILD]/src/out/logcat_dir"
     ],
     "cwd": "[SLAVE_BUILD]",
     "name": "logcat_dump"
   },
   {
     "cmd": [
       "[SLAVE_BUILD]/src/third_party/android_platform/development/scripts/stack",
       "--arch",
       "arm",
       "--more-info",
@@ skipping 37 matching lines @@
       "@@@STEP_LOG_LINE@python.inline@  os.remove(report)@@@",
       "@@@STEP_LOG_END@python.inline@@@"
     ]
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]