Do not override Navigator.share for insecure contexts

Navigator.share should not be added if the browser doesn't support it.

Bug: 1122059
Change-Id: I1f768ca5013bed212d6f24afdab44926f3e3042e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2391653
Commit-Queue: Mike Dougherty <michaeldo@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#804510}

ios/web/web_state/js/resources/share_workaround.js

@@ -14,8 +14,14 @@ goog.provide('__crWeb.shareWorkaround');
 
 /** @private */
 // Store originals to prevent calling a modified version later.
-const originalNavigator_ = navigator;
 const originalNavigatorShare_ = Navigator.prototype.share;
+// Navigator.share is only supported in secure contexts, do not create function
+// if it does not exist.
+if (!originalNavigatorShare_) {
+  return;
+}
+
+const originalNavigator_ = navigator;
 const originalReflectApply_ = Reflect.apply;
 const originalObjectDefineProperty_ = Object.defineProperty;