tools: enable stricter linting in lib directory

Enable ESLint 4.x linting and disable legacy linting in the lib
directory.

While doing this, some indentation in the .eslintrc.yaml file itself was
noticed to be incorrect. Fixed that too.

Backport-PR-URL: #14520
Backport-Reviewed-By: Anna Henningsen <[email protected]>

PR-URL: #14403
Reviewed-By: Anna Henningsen <[email protected]>
Reviewed-By: Yuta Hiroto <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Evan Lucas <[email protected]>
Reviewed-By: Timothy Gu <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Refael Ackermann <[email protected]>
Reviewed-By: Alexey Orlenko <[email protected]>

Author: Trott

.eslintrc.yaml

@@ -102,17 +102,17 @@ rules:
   func-name-matching: error
   func-style: [error, declaration, {allowArrowFunctions: true}]
   # indent: [error, 2, {ArrayExpression: first,
-  #                 CallExpression: {arguments: first},
-  #                 FunctionDeclaration: {parameters: first},
-  #                 FunctionExpression: {parameters: first},
-  #                 MemberExpression: off,
-  #                 ObjectExpression: first,
-  #                 SwitchCase: 1}]
+  #                     CallExpression: {arguments: first},
+  #                     FunctionDeclaration: {parameters: first},
+  #                     FunctionExpression: {parameters: first},
+  #                     MemberExpression: off,
+  #                     ObjectExpression: first,
+  #                     SwitchCase: 1}]
   indent-legacy: [error, 2, {ArrayExpression: first,
-                         CallExpression: {arguments: first},
-                         MemberExpression: 1,
-                         ObjectExpression: first,
-                         SwitchCase: 1}]
+                             CallExpression: {arguments: first},
+                             MemberExpression: 1,
+                             ObjectExpression: first,
+                             SwitchCase: 1}]
   key-spacing: [error, {mode: minimum}]
   keyword-spacing: error
   linebreak-style: [error, unix]

lib/.eslintrc.yaml

@@ -1,4 +1,13 @@
 rules:
+  indent: [error, 2, {ArrayExpression: first,
+                      CallExpression: {arguments: first},
+                      FunctionDeclaration: {parameters: first},
+                      FunctionExpression: {parameters: first},
+                      MemberExpression: off,
+                      ObjectExpression: first,
+                      SwitchCase: 1}]
+  indent-legacy: 0
+
   # Custom rules in tools/eslint-rules
   require-buffer: error
   buffer-constructor: error