Add cssnano

The CSS minifier we currently use (clean-css) is not maintained and
lacks support for new CSS features. CSSNano is a replacement that
supports features we need (primarily container queries).

This CL only adds the relevant dependencies, and does not use it. I will
do that (and remove clean-css) in a follow-up.

Bug: 1399763
Change-Id: I899ecc4482164404dd5ac2fd13f92fb797978e29
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/4092305
Commit-Queue: Jack Franklin <jacktfranklin@chromium.org>
Reviewed-by: Alex Rudenko <alexrudenko@chromium.org>
Commit-Queue: Alex Rudenko <alexrudenko@chromium.org>
Auto-Submit: Jack Franklin <jacktfranklin@chromium.org>
diff --git a/node_modules/postcss-normalize-display-values/LICENSE-MIT b/node_modules/postcss-normalize-display-values/LICENSE-MIT
new file mode 100644
index 0000000..fd0e863
--- /dev/null
+++ b/node_modules/postcss-normalize-display-values/LICENSE-MIT
@@ -0,0 +1,22 @@
+Copyright (c) Ben Briggs <beneb.info@gmail.com> (http://beneb.info)
+
+Permission is hereby granted, free of charge, to any person
+obtaining a copy of this software and associated documentation
+files (the "Software"), to deal in the Software without
+restriction, including without limitation the rights to use,
+copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.
diff --git a/node_modules/postcss-normalize-display-values/README.md b/node_modules/postcss-normalize-display-values/README.md
new file mode 100644
index 0000000..a2208d9
--- /dev/null
+++ b/node_modules/postcss-normalize-display-values/README.md
@@ -0,0 +1,44 @@
+# [postcss][postcss]-normalize-display-values
+
+> Normalize display property values with PostCSS.
+
+## Install
+
+With [npm](https://npmjs.org/package/postcss-normalize-display-values) do:
+
+```
+npm install postcss-normalize-display-values --save
+```
+
+## Example
+
+### Input
+
+```css
+div {
+    display: inline flow-root
+}
+```
+
+### Output
+
+```css
+div {
+    display: inline-block
+}
+``` 
+
+## Usage
+
+See the [PostCSS documentation](https://github.com/postcss/postcss#usage) for
+examples for your environment.
+
+## Contributors
+
+See [CONTRIBUTORS.md](https://github.com/cssnano/cssnano/blob/master/CONTRIBUTORS.md).
+
+## License
+
+MIT © [Ben Briggs](http://beneb.info)
+
+[postcss]: https://github.com/postcss/postcss
diff --git a/node_modules/postcss-normalize-display-values/package.json b/node_modules/postcss-normalize-display-values/package.json
new file mode 100644
index 0000000..6c35807
--- /dev/null
+++ b/node_modules/postcss-normalize-display-values/package.json
@@ -0,0 +1,36 @@
+{
+  "name": "postcss-normalize-display-values",
+  "version": "5.1.0",
+  "description": "Normalize multiple value display syntaxes into single values.",
+  "main": "src/index.js",
+  "types": "types/index.d.ts",
+  "files": [
+    "LICENSE-MIT",
+    "src",
+    "types"
+  ],
+  "license": "MIT",
+  "dependencies": {
+    "postcss-value-parser": "^4.2.0"
+  },
+  "author": {
+    "name": "Ben Briggs",
+    "email": "beneb.info@gmail.com",
+    "url": "http://beneb.info"
+  },
+  "repository": "cssnano/cssnano",
+  "bugs": {
+    "url": "https://github.com/cssnano/cssnano/issues"
+  },
+  "homepage": "https://github.com/cssnano/cssnano",
+  "engines": {
+    "node": "^10 || ^12 || >=14.0"
+  },
+  "devDependencies": {
+    "postcss": "^8.2.15"
+  },
+  "peerDependencies": {
+    "postcss": "^8.2.15"
+  },
+  "readme": "# [postcss][postcss]-normalize-display-values\n\n> Normalize display property values with PostCSS.\n\n## Install\n\nWith [npm](https://npmjs.org/package/postcss-normalize-display-values) do:\n\n```\nnpm install postcss-normalize-display-values --save\n```\n\n## Example\n\n### Input\n\n```css\ndiv {\n    display: inline flow-root\n}\n```\n\n### Output\n\n```css\ndiv {\n    display: inline-block\n}\n``` \n\n## Usage\n\nSee the [PostCSS documentation](https://github.com/postcss/postcss#usage) for\nexamples for your environment.\n\n## Contributors\n\nSee [CONTRIBUTORS.md](https://github.com/cssnano/cssnano/blob/master/CONTRIBUTORS.md).\n\n## License\n\nMIT \u00a9 [Ben Briggs](http://beneb.info)\n\n[postcss]: https://github.com/postcss/postcss\n"
+}
diff --git a/node_modules/postcss-normalize-display-values/src/index.js b/node_modules/postcss-normalize-display-values/src/index.js
new file mode 100644
index 0000000..7495e57
--- /dev/null
+++ b/node_modules/postcss-normalize-display-values/src/index.js
@@ -0,0 +1,71 @@
+'use strict';
+const valueParser = require('postcss-value-parser');
+const mappings = require('./lib/map.js');
+
+/**
+ * @param {string} value
+ * @return {string}
+ */
+function transform(value) {
+  const { nodes } = valueParser(value);
+
+  if (nodes.length === 1) {
+    return value;
+  }
+
+  const values = nodes
+    .filter((list, index) => index % 2 === 0)
+    .filter((node) => node.type === 'word')
+    .map((n) => n.value.toLowerCase());
+
+  if (values.length === 0) {
+    return value;
+  }
+
+  const match = mappings.get(values.toString());
+
+  if (!match) {
+    return value;
+  }
+
+  return match;
+}
+
+/**
+ * @type {import('postcss').PluginCreator<void>}
+ * @return {import('postcss').Plugin}
+ */
+function pluginCreator() {
+  return {
+    postcssPlugin: 'postcss-normalize-display-values',
+
+    prepare() {
+      const cache = new Map();
+      return {
+        OnceExit(css) {
+          css.walkDecls(/^display$/i, (decl) => {
+            const value = decl.value;
+
+            if (!value) {
+              return;
+            }
+
+            if (cache.has(value)) {
+              decl.value = cache.get(value);
+
+              return;
+            }
+
+            const result = transform(value);
+
+            decl.value = result;
+            cache.set(value, result);
+          });
+        },
+      };
+    },
+  };
+}
+
+pluginCreator.postcss = true;
+module.exports = pluginCreator;
diff --git a/node_modules/postcss-normalize-display-values/src/lib/map.js b/node_modules/postcss-normalize-display-values/src/lib/map.js
new file mode 100644
index 0000000..7f92128
--- /dev/null
+++ b/node_modules/postcss-normalize-display-values/src/lib/map.js
@@ -0,0 +1,45 @@
+'use strict';
+const block = 'block';
+const flex = 'flex';
+const flow = 'flow';
+const flowRoot = 'flow-root';
+const grid = 'grid';
+const inline = 'inline';
+const inlineBlock = 'inline-block';
+const inlineFlex = 'inline-flex';
+const inlineGrid = 'inline-grid';
+const inlineTable = 'inline-table';
+const listItem = 'list-item';
+const ruby = 'ruby';
+const rubyBase = 'ruby-base';
+const rubyText = 'ruby-text';
+const runIn = 'run-in';
+const table = 'table';
+const tableCell = 'table-cell';
+const tableCaption = 'table-caption';
+
+/**
+ * Specification: https://drafts.csswg.org/css-display/#the-display-properties
+ */
+
+module.exports = new Map([
+  [[block, flow].toString(), block],
+  [[block, flowRoot].toString(), flowRoot],
+  [[inline, flow].toString(), inline],
+  [[inline, flowRoot].toString(), inlineBlock],
+  [[runIn, flow].toString(), runIn],
+  [[listItem, block, flow].toString(), listItem],
+  [[inline, flow, listItem].toString(), inline + ' ' + listItem],
+  [[block, flex].toString(), flex],
+  [[inline, flex].toString(), inlineFlex],
+  [[block, grid].toString(), grid],
+  [[inline, grid].toString(), inlineGrid],
+  [[inline, ruby].toString(), ruby],
+  // `block ruby` is same
+  [[block, table].toString(), table],
+  [[inline, table].toString(), inlineTable],
+  [[tableCell, flow].toString(), tableCell],
+  [[tableCaption, flow].toString(), tableCaption],
+  [[rubyBase, flow].toString(), rubyBase],
+  [[rubyText, flow].toString(), rubyText],
+]);
diff --git a/node_modules/postcss-normalize-display-values/types/index.d.ts b/node_modules/postcss-normalize-display-values/types/index.d.ts
new file mode 100644
index 0000000..d2beadb
--- /dev/null
+++ b/node_modules/postcss-normalize-display-values/types/index.d.ts
@@ -0,0 +1,9 @@
+export = pluginCreator;
+/**
+ * @type {import('postcss').PluginCreator<void>}
+ * @return {import('postcss').Plugin}
+ */
+declare function pluginCreator(): import('postcss').Plugin;
+declare namespace pluginCreator {
+    const postcss: true;
+}
diff --git a/node_modules/postcss-normalize-display-values/types/lib/map.d.ts b/node_modules/postcss-normalize-display-values/types/lib/map.d.ts
new file mode 100644
index 0000000..ce08c76
--- /dev/null
+++ b/node_modules/postcss-normalize-display-values/types/lib/map.d.ts
@@ -0,0 +1,15 @@
+declare const _exports: {
+    clear(): void;
+    delete(key: string): boolean;
+    forEach(callbackfn: (value: string, key: string, map: Map<string, string>) => void, thisArg?: any): void;
+    get(key: string): string | undefined;
+    has(key: string): boolean;
+    set(key: string, value: string): Map<string, string>;
+    readonly size: number;
+    entries(): IterableIterator<[string, string]>;
+    keys(): IterableIterator<string>;
+    values(): IterableIterator<string>;
+    [Symbol.iterator](): IterableIterator<[string, string]>;
+    readonly [Symbol.toStringTag]: string;
+};
+export = _exports;