Only allow http/https scheme for proactive suggestions.

Previously non-http/https schemes were allowed.

Bug: b:143156047
Change-Id: I01074dc64dcb5f39e45f3198ad8897946d91090f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1873111
Commit-Queue: David Black <dmblack@google.com>
Reviewed-by: Tao Wu <wutao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#708381}

chrome/browser/ui/ash/assistant/proactive_suggestions_client_impl.cc

@@ -174,7 +174,8 @@ void ProactiveSuggestionsClientImpl::SetActiveUrl(const GURL& url) {
   // The previous set of proactive suggestions is no longer valid.
   SetActiveProactiveSuggestions(nullptr);
 
-  if (active_url_.is_empty()) {
+  // We only load proactive suggestions for http/https schemes.
+  if (!url.is_valid() || !url.SchemeIsHTTPOrHTTPS()) {
     loader_.reset();
     return;
   }