DevTools: add eslint as presubmit hook

third_party/WebKit/Source/devtools/PRESUBMIT.py

 # Copyright (C) 2014 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 # copyright notice, this list of conditions and the following disclaimer
@@ skipping 18 matching lines @@
 """DevTools JSDoc validator presubmit script
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
 for more details about the presubmit API built into gcl.
 """
 
 import sys
 
 compile_note = "Be sure to run your patch by the compile_frontend.py script prior to committing!"
 
+
+def _CheckDevtoolsStyle(input_api, output_api):
+    local_paths = [f.LocalPath() for f in input_api.AffectedFiles() if f.Action() != "D"]
+
+    devtools_front_end = input_api.os_path.join("devtools", "front_end")
+    affected_front_end_files = [file_name for file_name in local_paths if devtools_front_end in file_name and file_name.endswith(".js")]
+    affected_front_end_files = [input_api.os_path.join("front_end", file_name.split(devtools_front_end).pop()[1:]) for file_name in affected_front_end_files]
+    if len(affected_front_end_files) > 0:
+        lint_path = input_api.os_path.join(input_api.PresubmitLocalPath(),
+                                           "scripts", "lint_javascript.py")
+        out, _ = input_api.subprocess.Popen(
+            [input_api.python_executable, lint_path] + affected_front_end_files,
+            stdout=input_api.subprocess.PIPE,
+            stderr=input_api.subprocess.STDOUT).communicate()
+        if "error" in out or "warning" in out:

[paulirish, 2016/05/20 20:26:22]

You should use the exit code instead. 

Generally, it's expected to not have warnings break the presubmit (but using
exit code will address this)

[lushnikov, 2016/05/20 20:54:56]

Done.

+            return [output_api.PresubmitError(out)]
+        if "NOTE" in out:
+            return [output_api.PresubmitPromptWarning(out)]
+    return []
+
+
 def _CompileDevtoolsFrontend(input_api, output_api):
     local_paths = [f.LocalPath() for f in input_api.AffectedFiles()]
 
     # FIXME: The compilation does not actually run if injected script-related files
     # have changed, as they reside in core/inspector, which is not affected
     # by this presubmit.
     # Once this is fixed, injected_script_externs.js
     # should be added to the list of triggers.
     devtools_front_end = input_api.os_path.join("devtools", "front_end")
     if (any(devtools_front_end in path for path in local_paths) or
@@ skipping 73 matching lines @@
         for line_number, line in f.ChangedContents():
             if "/deep/" in line:
                 results.append(output_api.PresubmitError(("%s:%d uses /deep/ selector") % (f.LocalPath(), line_number)))
             if "::shadow" in line:
                 results.append(output_api.PresubmitError(("%s:%d uses ::shadow selector") % (f.LocalPath(), line_number)))
     return results
 
 
 def CheckChangeOnUpload(input_api, output_api):
     results = []
+    results.extend(_CheckDevtoolsStyle(input_api, output_api))
     results.extend(_CompileDevtoolsFrontend(input_api, output_api))
     results.extend(_CheckConvertSVGToPNGHashes(input_api, output_api))
     results.extend(_CheckOptimizePNGHashes(input_api, output_api))
     results.extend(_CheckCSSViolations(input_api, output_api))
     return results
 
 
 def CheckChangeOnCommit(input_api, output_api):
     return []