Conditionally invokes URI.tryParseURI in OSS code

Summary:
Conditionally invokes URI.tryParseURI in OSS code because it's not available in fbjs.

I am on the fence on this one, we need it internally but we can't break OSS consumers of Draft. I think the optional chaining operator with a fallback is a pretty conservative option, however it does look clowny af.

Differential Revision: D22722736

fbshipit-source-id: d8630899b88bd0961ed2e8be86ab25d4369d40d6

src/model/encoding/convertFromHTMLToContentBlocks.js

@@ -161,14 +161,24 @@ const isValidAnchor = (node: Node) => {
     return false;
   }
   const anchorNode: HTMLAnchorElement = (node: any);
-  return (
-    !!anchorNode.href &&
-    URI.tryParseURI(anchorNode.href) != null &&
-    (anchorNode.protocol === 'http:' ||
-      anchorNode.protocol === 'https:' ||
-      anchorNode.protocol === 'mailto:' ||
-      anchorNode.protocol === 'tel:')
-  );
+
+  if (
+    !anchorNode.href ||
+    (anchorNode.protocol !== 'http:' &&
+      anchorNode.protocol !== 'https:' &&
+      anchorNode.protocol !== 'mailto:' &&
+      anchorNode.protocol !== 'tel:')
+  ) {
+    return false;
+  }
+
+  try {
+    // Just checking whether we can actually create a URI
+    const _ = new URI(anchorNode.href);
+    return true;
+  } catch {
+    return false;
+  }
 };
 
 /**