Add packages to optimize svgs dynamically

These packages will be used to dynamically optimize SVG images
during the build.

R=jacktfranklin@chromium.org

Bug: 1216402
Change-Id: I04e95aa7d79c9d67beaf8a7861182c52b16b7d0f
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2939992
Reviewed-by: Jack Franklin <jacktfranklin@chromium.org>
Commit-Queue: Tim van der Lippe <tvanderlippe@chromium.org>
diff --git a/node_modules/css-tree/lib/parser/sequence.js b/node_modules/css-tree/lib/parser/sequence.js
new file mode 100644
index 0000000..44647e5
--- /dev/null
+++ b/node_modules/css-tree/lib/parser/sequence.js
@@ -0,0 +1,54 @@
+var TYPE = require('../tokenizer').TYPE;
+var WHITESPACE = TYPE.WhiteSpace;
+var COMMENT = TYPE.Comment;
+
+module.exports = function readSequence(recognizer) {
+    var children = this.createList();
+    var child = null;
+    var context = {
+        recognizer: recognizer,
+        space: null,
+        ignoreWS: false,
+        ignoreWSAfter: false
+    };
+
+    this.scanner.skipSC();
+
+    while (!this.scanner.eof) {
+        switch (this.scanner.tokenType) {
+            case COMMENT:
+                this.scanner.next();
+                continue;
+
+            case WHITESPACE:
+                if (context.ignoreWS) {
+                    this.scanner.next();
+                } else {
+                    context.space = this.WhiteSpace();
+                }
+                continue;
+        }
+
+        child = recognizer.getNode.call(this, context);
+
+        if (child === undefined) {
+            break;
+        }
+
+        if (context.space !== null) {
+            children.push(context.space);
+            context.space = null;
+        }
+
+        children.push(child);
+
+        if (context.ignoreWSAfter) {
+            context.ignoreWSAfter = false;
+            context.ignoreWS = true;
+        } else {
+            context.ignoreWS = false;
+        }
+    }
+
+    return children;
+};