Add a recipe to identify culprits for chromium compile failures.

scripts/slave/recipes/findit/chromium/compile.expected/compile_skipped.json

 [
   {
+    "cmd": [],
+    "cwd": "[SLAVE_BUILD]",
+    "name": "test r1"
+  },
+  {
     "cmd": [
       "python",
       "-u",
       "[BUILD]/scripts/slave/bot_update.py",
       "--master",
       "tryserver.chromium.linux",
       "--builder",
-      "linux_chromium_compile_rel_ng",
+      "linux_variable",
       "--slave",
-      "TestSlavename",
+      "build1-a1",
       "--spec",
       "cache_dir = None\nsolutions = [{'custom_vars': {'googlecode_url': 'svn://svn-mirror.golo.chromium.org/%s', 'nacl_trunk': 'svn://svn-mirror.golo.chromium.org/native_client/trunk', 'sourceforge_url': 'svn://svn-mirror.golo.chromium.org/%(repo)s', 'webkit_trunk': 'svn://svn-mirror.golo.chromium.org/blink/trunk'}, 'deps_file': 'DEPS', 'managed': True, 'name': 'src', 'url': 'svn://svn-mirror.golo.chromium.org/chrome/trunk/src'}]",
       "--root",
       "src",
       "--revision_mapping_file",
       "{\"src\": \"got_revision\", \"src/native_client\": \"got_nacl_revision\", \"src/third_party/angle\": \"got_angle_revision\", \"src/third_party/webrtc\": \"got_webrtc_revision\", \"src/tools/swarming_client\": \"got_swarming_client_revision\", \"src/v8\": \"got_v8_revision\"}",
-      "--issue",
-      "12853011",
-      "--patchset",
-      "1",
-      "--rietveld_server",
-      "https://codereview.chromium.org",
       "--output_json",
       "/path/to/tmp/json",
       "--revision",
-      "src@HEAD",
+      "src@r1",
       "--output_manifest"
     ],
     "cwd": "[SLAVE_BUILD]",
-    "name": "bot_update",
+    "name": "test r1.bot_update",
     "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@",
       "@@@STEP_TEXT@Some step text@@@",
       "@@@STEP_LOG_LINE@json.output@{@@@",
       "@@@STEP_LOG_LINE@json.output@  \"did_run\": true, @@@",
       "@@@STEP_LOG_LINE@json.output@  \"manifest\": {@@@",
       "@@@STEP_LOG_LINE@json.output@    \"src\": {@@@",
       "@@@STEP_LOG_LINE@json.output@      \"repository\": \"https://fake.org/src.git\", @@@",
       "@@@STEP_LOG_LINE@json.output@      \"revision\": \"f27fede2220bcd326aee3e86ddfd4ebd0fe58cb9\"@@@",
       "@@@STEP_LOG_LINE@json.output@    }, @@@",
       "@@@STEP_LOG_LINE@json.output@    \"src/native_client\": {@@@",
       "@@@STEP_LOG_LINE@json.output@      \"repository\": \"https://fake.org/src/native_client.git\", @@@",
@@ skipping 51 matching lines @@
     ]
   },
   {
     "cmd": [
       "python",
       "-u",
       "[SLAVE_BUILD]/src/tools/swarming_client/swarming.py",
       "--version"
     ],
     "cwd": "[SLAVE_BUILD]",
-    "name": "swarming.py --version",
+    "name": "test r1.swarming.py --version",
     "stdout": "/path/to/tmp/",
     "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@",
       "@@@STEP_TEXT@0.4.10@@@"
     ]
   },
   {
     "cmd": [
       "python",
       "-u",
       "[DEPOT_TOOLS]/gclient.py",
       "runhooks"
     ],
     "cwd": "[SLAVE_BUILD]",
     "env": {
       "GYP_CHROMIUM_NO_ACTION": "1",
-      "GYP_DEFINES": "component=static_library dcheck_always_on=1 fastbuild=1 gomadir='[BUILD]/goma' target_arch=x64 test_isolation_mode=prepare use_goma=1"
+      "GYP_DEFINES": "component=static_library gomadir='[BUILD]/goma' target_arch=x64 test_isolation_mode=prepare use_goma=1"
     },
-    "name": "gclient runhooks (with patch)"
+    "name": "test r1.gclient runhooks",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
   },
   {
     "cmd": [
       "python",
       "-u",
       "\nimport shutil\nimport sys\nshutil.copy(sys.argv[1], sys.argv[2])\n",
       "[SLAVE_BUILD]/src/testing/buildbot/chromium.linux.json",
       "/path/to/tmp/json"
     ],
     "cwd": "[SLAVE_BUILD]",
-    "name": "read test spec",
+    "name": "test r1.read test spec",
     "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@",
       "@@@STEP_TEXT@path: [SLAVE_BUILD]/src/testing/buildbot/chromium.linux.json@@@",
       "@@@STEP_LOG_LINE@json.output@{}@@@",
       "@@@STEP_LOG_END@json.output@@@"
     ]
   },
   {
     "cmd": [
       "python",
       "-u",
       "[SLAVE_BUILD]/src/testing/scripts/get_compile_targets.py",
       "--output",
       "/path/to/tmp/json",
       "--",
       "--build-config-fs",
       "Release",
       "--use-src-side-runtest-py",
       "--paths",
       "{\"build\": \"[BUILD]\", \"checkout\": \"[SLAVE_BUILD]/src\"}",
       "--properties",
-      "{\"buildername\": \"linux_chromium_compile_rel_ng\", \"buildnumber\": 571, \"mastername\": \"tryserver.chromium.linux\", \"slavename\": \"TestSlavename\", \"target_platform\": \"linux\"}"
+      "{\"buildername\": \"linux_variable\", \"buildnumber\": \"1\", \"mastername\": \"tryserver.chromium.linux\", \"slavename\": \"build1-a1\", \"target_platform\": \"linux\"}"
     ],
     "cwd": "[SLAVE_BUILD]",
-    "name": "get compile targets for scripts",
+    "name": "test r1.get compile targets for scripts",
     "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@",
       "@@@STEP_LOG_LINE@json.output@{}@@@",
       "@@@STEP_LOG_END@json.output@@@"
     ]
   },
   {
     "cmd": [
       "git",
       "diff",
-      "--cached",
+      "r1~1",
+      "r1",
       "--name-only"
     ],
     "cwd": "[SLAVE_BUILD]/src",
-    "name": "git diff to analyze patch",
+    "name": "test r1.git diff to analyze commit",
     "stdout": "/path/to/tmp/",
     "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@",
       "@@@STEP_LOG_LINE@files@foo.cc@@@",
       "@@@STEP_LOG_END@files@@@"
     ]
   },
   {
     "cmd": [
       "python",
       "-u",
       "\nimport shutil\nimport sys\nshutil.copy(sys.argv[1], sys.argv[2])\n",
       "[SLAVE_BUILD]/src/testing/buildbot/trybot_analyze_config.json",
       "/path/to/tmp/json"
     ],
     "cwd": "[SLAVE_BUILD]",
-    "name": "read filter exclusion spec",
+    "name": "test r1.read filter exclusion spec",
     "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@",
       "@@@STEP_TEXT@path: 'testing/buildbot/trybot_analyze_config.json'@@@",
       "@@@STEP_LOG_LINE@json.output@{@@@",
       "@@@STEP_LOG_LINE@json.output@  \"base\": {@@@",
       "@@@STEP_LOG_LINE@json.output@    \"exclusions\": []@@@",
       "@@@STEP_LOG_LINE@json.output@  }, @@@",
       "@@@STEP_LOG_LINE@json.output@  \"chromium\": {@@@",
       "@@@STEP_LOG_LINE@json.output@    \"exclusions\": []@@@",
       "@@@STEP_LOG_LINE@json.output@  }, @@@",
       "@@@STEP_LOG_LINE@json.output@  \"ios\": {@@@",
       "@@@STEP_LOG_LINE@json.output@    \"exclusions\": []@@@",
       "@@@STEP_LOG_LINE@json.output@  }@@@",
       "@@@STEP_LOG_LINE@json.output@}@@@",
       "@@@STEP_LOG_END@json.output@@@"
     ]
   },
   {
     "cmd": [
       "python",
       "-u",
       "[SLAVE_BUILD]/src/tools/mb/mb.py",
       "analyze",
       "-m",
-      "tryserver.chromium.linux",
+      "chromium.linux",
       "-b",
-      "linux_chromium_compile_rel_ng",
+      "Linux Builder",
       "-v",
       "//out/Release",
       "{\"additional_compile_targets\": [\"chromium_swarm_tests\"], \"files\": [\"foo.cc\"], \"test_targets\": []}",
       "/path/to/tmp/json"
     ],
     "cwd": "[SLAVE_BUILD]",
-    "name": "analyze",
+    "name": "test r1.analyze",
     "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@",
       "@@@STEP_TEXT@No compile necessary@@@",
       "@@@STEP_LOG_LINE@json.output@{@@@",
       "@@@STEP_LOG_LINE@json.output@  \"compile_targets\": [], @@@",
-      "@@@STEP_LOG_LINE@json.output@  \"status\": \"No dependency\", @@@",
+      "@@@STEP_LOG_LINE@json.output@  \"status\": \"No dependencies\", @@@",
       "@@@STEP_LOG_LINE@json.output@  \"test_targets\": []@@@",
       "@@@STEP_LOG_LINE@json.output@}@@@",
       "@@@STEP_LOG_END@json.output@@@",
       "@@@STEP_LOG_LINE@analyze_details@{@@@",
       "@@@STEP_LOG_LINE@analyze_details@  \"additional_compile_targets\": [@@@",
       "@@@STEP_LOG_LINE@analyze_details@    \"chromium_swarm_tests\"@@@",
       "@@@STEP_LOG_LINE@analyze_details@  ], @@@",
       "@@@STEP_LOG_LINE@analyze_details@  \"compile_targets\": [], @@@",
       "@@@STEP_LOG_LINE@analyze_details@  \"self.m.filter.compile_targets\": [], @@@",
       "@@@STEP_LOG_LINE@analyze_details@  \"self.m.filter.test_targets\": [], @@@",
       "@@@STEP_LOG_LINE@analyze_details@  \"test_targets\": []@@@",
       "@@@STEP_LOG_LINE@analyze_details@}@@@",
       "@@@STEP_LOG_END@analyze_details@@@"
     ]
   },
   {
+    "cmd": [
+      "python",
+      "-u",
+      "import sys; sys.exit(0)"
+    ],
+    "cwd": "[SLAVE_BUILD]",
+    "name": "report",
+    "~followup_annotations": [
+      "@@@STEP_LOG_LINE@result@[@@@",
+      "@@@STEP_LOG_LINE@result@  [@@@",
+      "@@@STEP_LOG_LINE@result@    \"r1\", @@@",
+      "@@@STEP_LOG_LINE@result@    \"skipped\"@@@",
+      "@@@STEP_LOG_LINE@result@  ]@@@",
+      "@@@STEP_LOG_LINE@result@]@@@",
+      "@@@STEP_LOG_END@result@@@"
+    ]
+  },
+  {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]