feat: implement googleFont addon

addon/googleFont.js

@@ -0,0 +1,43 @@
+'use strict';
+
+function createUrl (font, weights, subsets) {
+    var params = 'family=' + encodeURIComponent(font);
+
+    if (weights) {
+        if (!(weights instanceof Array))
+            weights = [weights];
+
+        params += ':' + weights.join(',');
+    }
+
+    if (subsets) {
+        if (!(subsets instanceof Array))
+            subsets = [subsets];
+
+        params += '&subset=' + subsets.join(',');
+    }
+
+    return 'https://fonts.googleapis.com/css' + params;
+}
+
+exports.addon = function (renderer) {
+    if (process.env.NODE_ENV !== 'production') {
+        require('./__dev__/warnOnMissingDependencies')('hydrate', renderer, ['put']);
+    }
+
+    if (renderer.client) {
+        renderer.googleFont = function (font, weights, subsets) {
+            var el = document.createElement('link');
+
+            el.href = createUrl(font, weights, subsets);
+            el.rel = 'stylesheet';
+            el.type = 'text/css';
+
+            document.head.appendChild(el);
+        };
+    } else {
+        renderer.googleFont = function (font, weights, subsets) {
+            renderer.raw = "@import url('" + createUrl(font, weights, subsets) + "');" + renderer.raw;
+        };
+    }
+};