DevTools: Make eslint mandatory and check node.js/npm modules in presubmit

third_party/WebKit/Source/devtools/scripts/lint_javascript.py

Index: third_party/WebKit/Source/devtools/scripts/lint_javascript.py
diff --git a/third_party/WebKit/Source/devtools/scripts/lint_javascript.py b/third_party/WebKit/Source/devtools/scripts/lint_javascript.py
index 9b8e77eb1eaddf8fd1a51201ee293e2e2e7ac49b..70a9c890651ff59a0c7cc8fdbf2bd5013c07dbf6 100755
--- a/third_party/WebKit/Source/devtools/scripts/lint_javascript.py
+++ b/third_party/WebKit/Source/devtools/scripts/lint_javascript.py
@@ -4,12 +4,13 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import os
 import os.path as path
 import re
 import subprocess
 import sys
 
+import install_node_deps
+
 files_to_lint = None
 
 if len(sys.argv) >= 2:
@@ -48,37 +49,16 @@ def to_platform_path_exact(filepath):
 scripts_path = path.dirname(path.abspath(__file__))
 devtools_path = path.dirname(scripts_path)
 devtools_frontend_path = path.join(devtools_path, "front_end")
-
-
-# Based on http://stackoverflow.com/questions/377017/test-if-executable-exists-in-python.
-def which(program):
-    def is_exe(fpath):
-        return path.isfile(fpath) and os.access(fpath, os.X_OK)
-
-    fpath, fname = path.split(program)
-    if fpath:
-        if is_exe(program):
-            return program
-    else:
-        for part in os.environ["PATH"].split(os.pathsep):
-            part = part.strip("\"")
-            exe_file = path.join(part, program)
-            if is_exe(exe_file):
-                return exe_file
-    return None
-
+eslint_path = path.join(devtools_path, "node_modules", ".bin", "eslint")
 
 print("Linting JavaScript with eslint...\n")
 
 
 def js_lint(files_list=None):
     eslint_errors_found = False
-
-    eslint_path = which("eslint")
-    if not eslint_path:
-        print("!! NOTE: Skipping JavaScript linting because eslint is not installed.")
-        print("!!   npm install -g eslint")
-        eslint_errors_found = False  # Linting is opt-in for now, so this is a soft failure
+    if not path.isfile(eslint_path):
+        print("Failed to run eslint, run ./scripts/install_node_deps.py to install eslint")
+        eslint_errors_found = True
         return eslint_errors_found
 
     if files_list is None:
@@ -87,7 +67,9 @@ def js_lint(files_list=None):
 
     eslintconfig_path = path.join(devtools_path, "front_end/.eslintrc.js")
     eslintignore_path = path.join(devtools_path, "front_end/.eslintignore")
+    (node_path, _) = install_node_deps.resolve_node_paths()
     exec_command = [
+        node_path,
         eslint_path,
         "--config", to_platform_path_exact(eslintconfig_path),
         "--ignore-path", to_platform_path_exact(eslintignore_path),
@@ -109,5 +91,3 @@ errors_found = js_lint(files_to_lint)
 if errors_found:
     print("ERRORS DETECTED")
     sys.exit(1)
-else:
-    print("OK")