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

scripts/slave/recipe_modules/chromium_android/example.expected/perf_runner_disable_location_basic.json

Index: scripts/slave/recipe_modules/chromium_android/example.expected/perf_runner_disable_location_basic.json
diff --git a/scripts/slave/recipe_modules/chromium_android/example.expected/perf_runner_disable_location_basic.json b/scripts/slave/recipe_modules/chromium_android/example.expected/perf_runner_disable_location_basic.json
index e0eeb09c5ccf18874789d8cb4a626ac56d5cdcdf..df86c8945fb16224b9262de2aa4940f1514997f5 100644
--- a/scripts/slave/recipe_modules/chromium_android/example.expected/perf_runner_disable_location_basic.json
+++ b/scripts/slave/recipe_modules/chromium_android/example.expected/perf_runner_disable_location_basic.json
@@ -278,7 +278,7 @@
       "[BUILD]/scripts/slave/daemonizer.py",
       "--",
       "[SLAVE_BUILD]/src/build/android/adb_logcat_monitor.py",
-      "[SLAVE_BUILD]/src/out/logcat_dir"
+      "[SLAVE_BUILD]/src/out/logcat"
     ],
     "cwd": "[SLAVE_BUILD]",
     "env": {
@@ -724,27 +724,6 @@
     ]
   },
   {
-    "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_2"
-    ],
-    "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.apk",
@@ -757,10 +736,7 @@
     "env": {
       "PATH": "[SLAVE_BUILD]/src/third_party/android_tools/sdk/platform-tools:[SLAVE_BUILD]/src/build/android:%(PATH)s"
     },
-    "name": "AndroidWebViewTest.install AndroidWebView.apk",
-    "~followup_annotations": [
-      "@@@STEP_NEST_LEVEL@1@@@"
-    ]
+    "name": "install AndroidWebView.apk"
   },
   {
     "cmd": [
@@ -789,47 +765,7 @@
       "--official-build"
     ],
     "cwd": "[SLAVE_BUILD]",
-    "name": "AndroidWebViewTest.Instrumentation test SmallTest",
-    "~followup_annotations": [
-      "@@@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_2"
-    ],
-    "cwd": "[SLAVE_BUILD]",
-    "name": "AndroidWebViewTest.logcat_dump",
-    "~followup_annotations": [
-      "@@@STEP_NEST_LEVEL@1@@@"
-    ]
-  },
-  {
-    "cmd": [],
-    "cwd": "[SLAVE_BUILD]",
-    "name": "unittests"
-  },
-  {
-    "cmd": [
-      "[BUILD]/scripts/slave/daemonizer.py",
-      "--",
-      "[SLAVE_BUILD]/src/build/android/adb_logcat_monitor.py",
-      "[TMP_BASE]/logcat_tmp_3"
-    ],
-    "cwd": "[SLAVE_BUILD]",
-    "env": {
-      "PATH": "[SLAVE_BUILD]/src/third_party/android_tools/sdk/platform-tools:[SLAVE_BUILD]/src/build/android:%(PATH)s"
-    },
-    "name": "unittests.spawn_logcat_monitor",
-    "~followup_annotations": [
-      "@@@STEP_NEST_LEVEL@1@@@"
-    ]
+    "name": "Instrumentation test SmallTest"
   },
   {
     "cmd": [
@@ -851,26 +787,7 @@
     "env": {
       "PATH": "[SLAVE_BUILD]/src/third_party/android_tools/sdk/platform-tools:[SLAVE_BUILD]/src/build/android:%(PATH)s"
     },
-    "name": "unittests.unittests",
-    "~followup_annotations": [
-      "@@@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_3"
-    ],
-    "cwd": "[SLAVE_BUILD]",
-    "name": "unittests.logcat_dump",
-    "~followup_annotations": [
-      "@@@STEP_NEST_LEVEL@1@@@"
-    ]
+    "name": "unittests"
   },
   {
     "cmd": [
@@ -899,10 +816,10 @@
       "python",
       "-u",
       "[BUILD]/scripts/slave/tee.py",
-      "[SLAVE_BUILD]/src/out/Release/full_logcat",
+      "[SLAVE_BUILD]/src/out/Release/full_log",
       "--",
       "[SLAVE_BUILD]/src/build/android/adb_logcat_printer.py",
-      "[SLAVE_BUILD]/src/out/logcat_dir"
+      "[SLAVE_BUILD]/src/out/logcat"
     ],
     "cwd": "[SLAVE_BUILD]",
     "name": "logcat_dump"
@@ -913,7 +830,7 @@
       "--arch",
       "arm",
       "--more-info",
-      "[SLAVE_BUILD]/src/out/Release/full_logcat"
+      "[SLAVE_BUILD]/src/out/Release/full_log"
     ],
     "cwd": "[SLAVE_BUILD]",
     "env": {
@@ -938,7 +855,7 @@
     "cmd": [
       "[SLAVE_BUILD]/src/build/android/asan_symbolize.py",
       "-l",
-      "[SLAVE_BUILD]/src/out/Release/full_logcat"
+      "[SLAVE_BUILD]/src/out/Release/full_log"
     ],
     "cwd": "[SLAVE_BUILD]",
     "env": {